What has that got to do with budget? Speaker wattage ratings aren't very useful for determining amp needs, more about sensitivity and impedance (and generally avrs are suited for 6/8 ohm speakers, sometimes for lower impedance speakers at high levels another amp solution (like external amps) might be a thought, so might want an avr with pre-outs to accommodate such.
The subwoofer is a passive sub? Most avrs (except for some htib type) won't work as they don't have an amplified sub channel.
Might play around with this to determine your amp power needs
http://myhometheater.homestead.com/splcalculator.html