0o, you want five speakers, a subwoofer, and a receiver, all for $1000? That's a tough one. Perhaps someone else can come up with something. You can get "something" but it's performance in that area will be disappointing.
consider, for a room that size most of your initial $1000 will be spent on a subwoofer.
You can get a decent entry/mid level receiver for about $200 - 300 if you don't mind a good refurb with a guarantee.
for a decent set of five speakers you can figure on at least another $1000 - $1250.
The job of a speaker is to move air. the larger the area of the room, the more air it has to move. In subwoofers, there is no substitute for power and size.
Check out
http://www.svsound.com/ and
http://www.hsuresearch.com/ to get a feel of what we're facing here.
If this meets your approval, I'm pretty sure many recommendations will be forthcoming.