Okay, my plan would be to get plenty of rest tonight somehow, take sleeping meds if you have to. You will need to be rested so that you can think of amazingly perfect responses to everything. Tell your friend tomorrow that you really like this girl and would appreciate it if he would STFU and GTFO, but in a nicer way. If he laughs or says something to try to offend you, tell him you'll owe him a favor later on. Even if he says no, he is PROBABLY concerned in some way. Whether this does or doesn't work, go to a pay phone (or any other phone that's available). Talk to her, comfort her, then gently imply your feelings. Wait a while, probably a day or so, then talk to her again, and imply, but do not immediately say, your feelings toward her. Also, I wouldn't "flirt" as it may make you seem too straight-forward. Then, wait a bit longer, then ask her if she wants to go see a movie or get dinner, or whatever you feel comfortable with. After that, I can only hope for you.
This is my suggested plan, I am not saying that you should or have to follow it, it just seems like a good idea to me. I'll be praying for you, make sure to let me (or all of us) know how it goes. I just want you to know I won't be happy if you chicken out. Be brave, that first call is always the hardest. You can do this, man.