i would look to buy all this stuff online because it will be WAAAAY cheaper... my local fish stor charges $40 for a powerhead that i can get for $18 online, and for skimmers there is a much bigger difference in price.
Dr. Foster and Smith have good prices and great shipping/customer service. For a skimmer an Octopus BH100 would be good for your tank, thats what i have and im
very pleased with it. For powerheads, Koralia's are very nice but MaxiJets are nice also and much cheaper (also what i have - 2 maxijets 600/900).
Look at Dr.Foster and Smith for powerheads and google around for the skimmer.