PS3 Problems, please help?

My playstation 3 has been experiancing problems today. While playing modern Warfare 2, the game is very jerky, and im jumping around alot. its causing me to do very poorly in the game. i tried several things... leaving the game, entering a new one, different game modes,turning off my system, loging out, and back into psn, nothings helping. I DO have a wirless conection, but when i check the connection it says full bars. today is the first day this has been happening. my warrenty hasnt expired, and wont for another month or two, should i return my ps3 for a new one? and if so, who would i contact? the place where i bought it from, or sony?