The numbers you are seeing is the amount of channels a receiver can handle

The first number (normally 5 or 7) is for 5 channel surround (2 fronts, 2 surround and a centre speaker) or 7 channel surround (2 fronts, 2 surrounds, 2 rears, and a centre) 

The second number (normally 1 or in expensive receivers 2) is the amount of subwoofers that can be handled by the receiver.

If you are looking to power only 2 speakers you can pick up a 2 channel receiver. Examples below.

http://www.futureshop.ca/en-CA/category/stereo-receivers/10573.aspx?path=efc014fcb15aeb4ce5cfb518b8b...