Hey achani1,
I can't help but notice you sound distressed.
Hang in there we will chime in to help make your decision.
First of all, that's a pretty large room. So you might step up another $100 or so to get the proper sub for that size of room. Usually one needs to spend around $600 minimum to get the kind of sub you will need. I don't really have enough information from you to give you the proper suggestions (i.e. music preference, the amount of listening time you will do with music as compared to movies - usually expressed as a ratio in percentage form, whether you live across the border from U.S., etc. etc.
But, I can tell you that in the $600 range you can buy a sub from SVS (SV subwoofers), HSU or Rocket if you live in the U.S. If across the border than it will cost you more money. If say you're in Canada, then PSB or Paradigm may be what you need (price lower than here in the states).
You might want to give us a little more information in order for us to help you out further.
Also you might want to check out each manufacturers website. I don't have the links, but you can easily google them.
Here is the list of suggested subs:
SVS - any of the ISD models (good for music and movies but lean towards movies)
HSU - VTF-3 MKII (good for both music and movies. Same as above)
Rocket UFW-10 (excellent for music, better than the others, but not so good with movies) (BTW if using google, search "AV123" to get to their website)
PSB - Subsonic 6i is the best overall performer for the price for this manufacturer) (Too expensive here though)
Hope that helps. Good luck, and reply back to us with more info. or at least let us know what you purchased and how it sounds.
