How I can replace my smd power push-botton?

I have a samsumg galaxy s2 sgh-t989 from t-mobile, that i boughted from a friend; but it turn-out that the power botton was falty and it was already falling apart. After 3 week of use it totally went-off of the mainboard, so I tried to resoldered back with my fine tip soldering iron. Nevertheless i did put it back, but it was turning on and reseting itself back-and-fort. So i notice that it has 4 little contact points were soldered to the base make a continues ground. After several attempts of resoldering i knew that i need a heat gun which i didn't had at the movement; but now i think that i new a new push botton to be installed so it could function as a new phone back. Anyone that can help me out and tell me where a can buy a new power smd push botton for my phone. Thanks