Hockeyfan

Hey, I just joined the forum and need some opinions/recommendations for a sub. I have the Icon w series which includes a pair of wf-35's, pair of ws-24's for surrounds, and the wc-24 as my center. Right now i'm running the speakers on my yamaha rx- a2000. My room dimensions are 25' by 15' and 12ft high. Should I go for just one sub or two? Also what kind of sub would pair up nicely with the icon w series? I watch a lot of movies, and play music and video games frequently as well. My budget is $1000 and under I appreciate any recommendations or advice you guys have. Thanks, Sean