For $1k you aren't going to get much of an upgrade over what you have (unless you go used as Erik suggests). I'd say you're probably better off saving up.
Your pioneer isn't a bad reciever. You can take advantage of the PRE out available and add a 2 channel amp to driver your front speakers. this should give you improved 2 channel sound as well. However, you're still going to have trouble finding a good amp for $1k.
Jerry