That would all depend on your use....i.e.desired listening levels and how far away from the speakers you will be. It will be fine up to a point....but I'd start with what you've got and then worry about changing the receiver later (since you cannot add amps to this receiver).
Your local hardware or home improvement type store is one option for speaker wire generally (in bulk, without connectors), or specialized sellers like monoprice.com or a whole bunch of others....try this for information about speaker wire in general, particularly the wire table for assistance in determining the gauge you need for the length you need
http://roger-russell.com/wire/wire.htm
