Re: what to do. emergency!
Have you read the advice from your other posts? I think you should...
It depends who is in the wrong... Honestly, if you're in the wrong then say sorry. On the other hand, if she is wrong, don't just forget about it then buy her a gift for her birthday.
Try and sort out the argument without getting angry and shouting at each other. It doesn't solve anything. Just sit down and talk about it.
If I were you, I wouldn't get her anything for her birthday unless you're quite good friends regardless of you fancying her. It may seem like you're trying to win her over with presents, and to most girls, it doesn't work.