Questionnnnnn.

I'm planning on getting new interior speaker for my Regal, all 4 of them.
I have like two 5-1/4"s and two 6x9"s I think.
I'm looking to connect them up to an Amp I guess, my sister's boyfriend said if I did it would bump up the wattage and make the bass/speakers louder(possibly saving me from having to buy a sub)
I was just wondering if anyone knows what speaker combination+amp I could use to do this, Money isn't really an issue.