its true that u cant make someone love you. but she may still love you, so therefore you have a chance. firstly, why did you break up? whos fault was it?? if it was something you did, you need to convince her that you are sorry and everything will be okay. you will make things better again, make sure she knows you are willing to do anything to make it work again. If it is something she has done, make sure she knows you forgive her and that it is okay.
whatever happens, dont give up. she may be testing you and seeing how much you really love her. so show her that you do. dont be put off by the fact that it didnt work when you took her flowers round. if you keep trying and she loves you enough, she will come round!
though there is only as far as you can go. a couple of weeks is probably enough, and if she hasnt changed her mind then id give up to be honest. she may be enjoying the attention shes been getting from u trying to get her back, so if you give up she may even then realise how much she misses you and ask for you back. or she may not. and if she doesnt its her loss. you tried as much as u can!