Its hard to get anything decent for that price range. YOur best bet would be save up a little and maybe use that 400 for just speakers. If not, Onkyo makes some good Htib's that include a receiver and speakers that should give you a good start.
Heres a good 5.1 set
http://www.epinions.com/Onkyo_HT_S65...ems_HT _S650#
Heres some reviews along with other decent set ups.
http://reviews.cnet.com/4502-6740_7-...v.onk&qt=Onkyo