OMG this thread has made me giggle!! You cant live with us and you cant live without us eh!!
Be glad us females arnt all like your gf. What the heck is going on!!! Why on earth does she expect you to buy her a phone let alone anything else? If she cant afford it, then she doesnt have it. After dropping one in the bath you were generous enough to buy, I'd not even consider getting her another.
And after the latest update, why are you still with her? She sounds far more than imature to me. Can you really see yourself happy in a few years??? Just my opinion but life with someone should be fun not fight. I know we all have ups and down (and the fun ones are good!!) but generally you should be happy, not spending your days walking on egg shells worrying. Take a hard look at the life you have with her and think if its what you really want. If you do split, time heals. I agree with Nige, maybe you didnt give yourself long enough before you got together with her.
Good luck in what you decide to do, just be happy.