You don need another amp.

All you need is another set of speakers in another room. That's the great thing about having a 7 channel receiver, you use the 2 unused amp channels to power the second zone (unless you have a 7.1 surround configuration) Your 525 will act as the pre amp and power amp for zone 2.

The only trick is getting the additional speakers inconspicuously wired to the second zone from the 525.