An integrated amp is a step up from receivers. So, separates are 2 steps up from a receiver.
The 7140 is only 40w. Were it me, I'd get the pre (if working properly) and then look for a stand alone amp with at least 100w.
If you become a subscribing member (click on subscribe in the upper header), for $25 per year you get access to Barter Town. BT is a forum where members buy, sell and trade with each other. Mostly audio, but there are other categories. Currently on BT is a SAE amp, at a good price. I know nothing about that brand, so you would want to research it.