Jazz Virtual Instrument recommendations

[makingitup]

I'm a newbie and I'm maybe in the wrong forum. If anyone can point me in the right direction or give advice, it would be greatly appreciated.

I'm a solo jazz musician. I've always been my own roadie, so I have to minimize the loading/unloading, especially as I get older. My dream has always been to have the few instrument sounds I need for gigging in the smallest package. Every module or keyboard I have is lacking in two or more of the sounds I want.

So I've bought a Receptor rev C with version 1.7. I would like to upgrade the RAM and install a SSD to quicken booting and loading of instruments. But I'm not sure I need extra horsepower considering the limited sound set I'm seeking. I play left hand bass on a split keyboard and would like to have Acoustic Bass, Electric Bass and Fretless Bass. My right hand instruments are Acoustic Piano (anything out there better than or close to Ivory?), Rhodes, Wurlitzer, Vibraphone and a few fixed B3 sounds.

1) I'd like opinions on how to acquire my sounds and spend the least money, but I don't mind paying as long as I am not also purchasing dozens or hundreds of other instruments in which I have no interest.
2) Do I have enough horsepower to quickly change among these instruments on gigs with only 2g of RAM and a rather slow 400g IDE HD?

Any and all help accepted.

--Joe