Well, first of all, if you have the USB cable that came with the phone, plug it into a USB port on your laptop or computer. That will charge it.
The USB port on the newer phones is called a "micro" USB connector. If you examine it, you'll see the end connector (that goes into the phone) is smaller and "flatter" they a typical USB connector. You should be able to find a charger that works. First of all, your local T-Mobile store should have a replacement for it. You can try BestBuy or some of the other electronic stores.