Welcome to Audiogon, Lawlass!
Given your statements about the condition of the amplifier and the speakers, and your satisfaction with them, it sounds like the first priority should be to purchase source components and a preamplifier. Decisions about upgrading the amp and/or speakers, or perhaps having them professionally refurbished with new capacitors (which may already not be performing as well as they did during the 1980s, especially in the case of the amplifier) could be deferred until a later time.
The gain, impedance, and other technical characteristics of the Stasis 2 are compatible with a wide variety of modern preamplifiers and other "front end" components. For specific recommendations it would be helpful to know the budgetary range you have in mind, and also whether your interests are in playing LPs, CDs, material that is streamed or downloaded via the Internet, other kinds of source material, or some combination thereof.
One final observation: I, and I believe most here, would not consider a 1000 square foot listening space to be "small." :-)
Best regards,
-- Al