Watt Puppy 7 needs new or used Amp and Pre-amp

I'm building my system on a pair of Watt Puppy 7 speakers. Currently I have my vintage Marantz 250 amp with an SAE Mark 1B Pre-amp/equalizer.
I think the preamp needs to be replaced first. I need some advice on putting together a system on a tight budget. Thanks for helpful advice!
Duane