Merlin and Bike Discount usually have cheap DT swiss wheels for $300. I'd steer you toward getting a set of ER1600 32 wheels and put road tires one them. Use the stock wheels for your slow tires.
Otherwise, It's not the weight of the wheels making your feel slow,it's the tires rolling resistance. 2-300g of rim weight only makes a 1-2% difference in energy needed to spin up the wheel, which doesn't take that much energy in the scheme of things.