I'm not a big fan of 'sealing' a floor. Concrete is somewhat meant to 'breath' unless you're SURE that moisture isn't coming up through the concrete. If you're temporarily covering it, how 'bout some area rugs or carpet remnants?
I'm not sure how far along you are w/your project but visit your local Paint Retailer (found in the YELLOW PAGES under PAINT - RETAIL) for guidance.