You need to provide more information. We need to know your CPU and RAM as those can bottleneck your gpu's performance.
http://www.newegg.com/Product/Prod [...] 6814187061 is probably the best low profile card on the market, although it has mixed reviews. If you plan on gaming you need a larger case for airflow and cooling
You computer brand and model number (if pre-built) would help. Power supply info (if you know it - we might be able to get it from your PC model number).