You don't need anemones to keep Clowns. All Clowns don't host in anemones in an aquarium.
I wouldn't think about an anemone right now...they need alot of light and an established tank, so you are looking at maybe a year down the road before you could
get one. I agree with those guys above...I wouldn't get one at all. If they get caught in a powerhead they could kill your whole tank...especially one that small.
I agree, you will need to recycle the tank. Aragonite sand is a good option. Skip the live sand...yours will become live eventually. I would get more like 10-12lbs of live rock. And then you'll need some light depending on what you want to keep. I would get some chaeto to put in your filter...take the filter media out and just stuff it with chaeto...you'll need a little light for it though. And it wouldn't hurt to get a powerhead. A Koralia nano or 2 would be perfect for a 10g.
The lighting you'll need will depend on what corals you want to keep. Do you have any in mind?
edit: You guys beat me by 3 mins! That is what I get for talking on the phone and typing.