Em, okay it's clearer now. With your budget I'd suggest M22s plus QS4s for excellent sound, but that a center speaker isn't an immediate necessity. The M22s can play the center material and form a "phantom" center which is okay except that the center image then shifts to the left or right for someone not in the center.
As to the sub, no, the sub amplifier powers only the sub itself. Even when a speaker is connected to the output terminals on the sub, that just sends the power from your receiver straight through the sub and on to the speaker, so the receiver is the relevant consideration. If you'd give us a sub budget we could suggest some inexpensive candidates.
