Shakespearian Tragedy

I feel like I'm in a Shakespearian Tragedy of some kind...any advice would be appreciated.
I've been a Taxi Driver for the past 21 years. I'm 46 years old, been married for 22 years to the same woman, it's my first and only marriage.
The first six years or so, we had a perfect marriage. I was in love with her, and I believe she was in love with me, we hardly ever disagreed about anything, and never had fights. Then, in October of 1994, I was shot while driving my Taxi. The bullet went in just in fornt of my right ear, and traveled up towards my brain, then turned down and exited right behind and below my left ear. As it left, it clipped my corodid artery. I lost ALOT of blood very fast. At the hospital, they told my wife that I wouldn't make it, but that if I did, I'd be a vegetable. She prepared for the worst.
I spent three days in a coma and on life support, but I came out all right. The week I went home from the hospital, my wife threw me out, and I had to go let my motgher take carte of me for a week. I figured she had been through too much and couldn't deal, so I cut her slack. Finally, when I went back home, things were NOT the same. I eventually healed and went back to work, but the dammage to my marriage was beyond repair.
Shortly after I was back up and going, she announced that WE were not having sex anymore. I asked why, she only said she didn't want it anymore.
I did alot of thinking, and decided to stay with her anyway. That till death do us part seemed to have not loophole. I made the best of it. It's been fifteen years, and several years ago, she had a heart attack. She didn't follow the Doctor's instructions, and her health has suffered, so that now she has heart trouble, congestive heart failure, highn blood pressure, is five foot tall, and over three hundred pounds. Recently she has developed kidney problems. She not CANNOT have sex, and I suppose she feels bad about things. She has tried to get me to find a girlfriend to take care of me, and be there if anything happens to her...I've refused several times.
In the course of my job on the night shift, I meet all kinds of people, mostly hookers and drug dealers, drunks, and crack addicts. All the hookers and addictas have sad stories, but admit their drug habit is their own fault.
One night, a few years ago, I met one particular young woman. She was a hooker and an addict, but was trying to get clean for her 15 year old son. She would leave town for awhile, get clean, and when she came back, stay with the guy who was raising her son...not the father though. She had no where else to go, other that back to the neighborhood where she would be exposed to the same drugs and people as before, but the guy wonl't let here stay there without sex. One particular kind that she wouldn't even do while hooking. Things would be OK for awhile, then he'd want that, she'd refuse, and he'd talk bad to her till she finally gave up, did it, and ended back on the drugs for feeling like trash.
I saw her go through this several times, but couldn't help her.
On nigh, I saw her while she was still clean.I was having a rough time of it because of my situaltion, and knowing my well, she knew my situation. She offered the only thin g she had to give to make a friend feel better, and relive my depression. She said that anytime I needed her, come to her. She'd never charge me. Ofcourse I couldn't accept her offer, but she offered in good faith the only thing she knew, and all she had.
Several weeks ago, she disappeared again to get off the stuff, and I got to thinking about the usual course of events. The more I thought, the madder I got. Started having headaches, and ill temper for no reason.
Then I talked to another girl I knew...she had no intention of getting off the stuff, but was friends with my girl, and was always kinda soft for her situation. Suddenly she asked me if I'd told her that I was in love with her.
I was thunderstruck... I said "what did you say?"
She said it was pretty obviouse, that all the people on the streets knew it. Surely I knew.
Back at the Cab Lot, my coworkers started asking me what was wrong...I told them, they said the same thing.
That's when I relized that, despite all I could do, despite 22 years of driving a cab, and knowing better, despite being faithfull to my wife all these years, I had fallen for this girl.
She stayed gone for five weeks, and got clean as usual. She went to here guy friend's house, as usual. But since I realized that I was in Love with her, I haven't sheen here or talked to her. I'm CRAZY with worry, and can't think.
I need advice, because if I can't get to here before the pervert starts on here again, she'll be right back in the same situaltion, and I need to let here know the truth.
I just don't have anyway to talk to her, and don't know what to do if I could.
Please, someone give me some hope, and advice.

Oh and BTW, I have no intention of trying to "save" her. She's shown that, with the right support, she can do that all by herself.

well, since you love her, did you talk to your wife about it? i know she told you that you can go get a girlfriend but despite it all, she is still your wife.
and about this girl you like. you want to find her right?
well the only thing you can do is talk to her friend as thats the only link you have to her right?