Limited budget-spend more money on amp or preamp?

Hi. I am new to decent sound. I have a OK pair of full-range speakers (Von Schweikert VR-2000's) and are now looking for something to power them with. I am very limited with funds now, and am looking for decent used gear (both an amp and preamp). Out of the two components, would money be better spent on a good amp that I will be happy with for several years and a budget preamp, or the other way around? I have been looking at both a Bryston .4B Linestage and a Bryston 3B/4B amp, but I can't afford both. If I go with the .4B preamp, I will have to cut corners on the amp (probably an Adcom 545II). Likewise, if I get the 4B amp, I will have to get a cheaper preamp-something used under $150.

What combo would give me the best sound? Thanks in advance!