3500mah

i Have Samsung Galaxy S2. i need to buy a new Battery for my fone, as the old one is not working. Pls tell me Guys which one to Buy ? Which is better ? The Current i m using is Samsung OG Battery, it got a bit blown out& not working in just a Year. 1. 3500mAh --> RS.1100 {dUPliCATE} {eBay}...