To me it sounds like you are wasting your time with this girl, after you had given her a ride home you should have no contacted after that. If she texts you to say thank you there is no need to reply and start an argument or rile more emotions up in her with bitter responses.
It sounds to me like you were getting too serious too soon with this girl, and that maybe you should have held back with showing any real emotion at least until she tells you she wants to be with you. Read this thread.
http://www.sosuave.net/forum/showthread.php?t=40241
Its sometimes hard to not feel the strong emotion that makes you want to just jump straight in and never let go of her, but women do not want a man like this, at least not at the start. You need to try and distinguish between strong feelings and reality, often we are deceived by our own brains telling us that something is worth more and means more than it really is. And often we only see this a while after we have lost this 'precious' thing.
If she thinks of you as a clingy guy, there is nothing but time that will change this, the more you try to reason it away with her the worse it will get. You need to stop seeing her, re-evaluate and decide whether or not this is the truth, and be honest with yourself. And if it is, decide if you want to change (if so there is easily enough reading material here to get started).
If this guy is your buddy, for starters, he got there before you, you cannot hold that to him, and unfortunately it may so happen that she isnt finished with him in her mind, and thats not his fault. Even if he doesnt want her, the fact you are connected with him will never make you the prize to her, so she wont be able to use you to move on from him. You aren't that new mysterious guy that she is completely blown away by to the point where she forgets all about your buddy. Its the harsh truth, in all honesty it seems like a road thats going nowhere. So dont hold it against him.
If you want her, get over her. As right now she thinks of you as a desperate loser that she has in the palm of her hand if she wants you. You are the prize and you need to establish that within your own mind before she will. Make her work for you if she wants your attention. You did a good thing in terms of being a gentleman picking her up in a state (I dont think, in context, this was a beta thing to do), but dont make a big deal out of it and dont even contact her about it (again). Act as if it was nothing, and she means nothing to you.
So you have two options,
1) forget her and move on. She might come back but if she doesnt then who cares you will have met new women anyway and you wont care.
2) keep trying to chase her, argue, reason with her and make the situation a million times worse. You cannot change a girls perception of you instantly, its a process that has to come from inside you, and that will reflect out onto others and maybe eventually she will notice that you have changed. But its a long long process, sometimes years, before a girl might believe that.
Edit:
Also, the very fact you texted her shows that you care. She knows this, and instantly doesn't give a crap about you. It comes across very needy and whiney. If you were a man, you take it on the chin, you get over it, IT DOESNT BOTHER YOU. As soon as you can realize this attitude it will bug the hell out of her. Next time you hear that sort of stuff has been said by her to your friends or hers, just laugh at it and smile. If that gets back to her, believe me that will bug the sh*t out of her. You need to take control of the situation and ultimately your life. You dont need her, you might want her, but you dont need her. Never complain to your friends or hers about her, literally just pretend like she never existed. If you start whining, its unnatractive to women you might want to consider seeing in the future and it will get back to her, and she will know you arent over her.
Good luck. Just my two cents
