confused about amp

I just bought some Soliloquy 5.3 speakers to use as my mains and HT and for music. The center and other speakers will follow soon.

I want to upgrade my amp but still being somewhat new to this, I don't know the best route. I currently have a Yamaha RXV-995 receiver. 100x5, DD, DTS, etc.

Should I use the yamaha as a pre?
buy another pre and use the yamaha as a power amp?
what about a tubes?
How many channels are really needed? I'd hate to waste the money on 5 channels if you really only need 3 and not therefore not get as good music performance for the same money.

I don't want to spend a fortune. I'm looking for something used/demo for $700-1000.
Ishoulda read this thread before I just responded to the 5.3 vs 5.0 thread ... so you decided on the 5.3 or are you vacillating? Anyway , on topic ... what I'd do (and did) is add a good quality 2ch amp and use the receiver as the pre, and use its own amps for the center and surrounds. Down the road decide if further improvement in 2ch is preferred (and add a 2ch pre) or multi-ch/surround/HT improvement is what you want (and add prepro & more high quality amp channels). Of course, source improvements help with either at any time. YMMV
I went ahead and bought a demo pair of 5.3 here on audiogon yesterday. Think I did ok, paid $1250 shipping included for them.

I guess I have time to decide on amps. have to pay off a HDTV, these speakers, and 2 upcomming vactions first. But I would like to know which way to go. I thought about doing exactly what you mentioned, but I get alot of bad talk about my yamaha receiver here, so it makes me wonder.
Dont mind the bad talk about your yamaha reciever.Inscrutable gave excellent advice,thats the way I did it and that is what I reccommend to any who ask.It makes for a conveinant way to upgrade continually and still have working theater and 2 channel.Besides,if the luxury of having 2 seperate systems ever arises you cant ask for a better easier way to make the movE.
If your budget is limited (as at least mine is) I would advise either obtaining two monoblocs for the main speakers (if music is a priority) and a three channel amp for the other speakers, OR a good five channel amp (I own the EAD PM2000 and am very satisfied). I would use the Yamaha as a pre/pro for now. I would recommend investing in a source component next, followed by a new pre/pro. I can't say I have experience doing all of this, but after a few years contemplating the process, given a limited budget at least in the short term, this is the plan I have come up with, for what it's worth. (I use a Yamaha DSP-A3090 as a pre/pro with martin logan speakers and am planning to buy a Muse thalia soon as my next investment in a long term process). Hope this helps.>
Another way to go is to get an integrated amp with HT bypass. You can use the Yamaha for HT only, using it's amp to power center and rear speakers. This assumes your Yamaha has pre-outs for the front channels.