Sounds like you miht be a bit fast when coming in. Try coming in a bit higher then slipping to get down, that way you don't pick up the airspeed. Also if you flare it a little bit higher than normal, you'll get it right down with little float. I would not retract the flaps unless they are the manual type, otherwise you could risk retracting the gear aswell.
I think the 172 (not sure about the RG) recommend 62 kts, you might need to be a bit slower than that to minimize float, because with 62 kts you will still get a bit of float.