Yes, it copnnects to the reservoir in place of the cap. You pressurize to 20PSI and then bleed the calipers in sequence (also the slave as it shares the same reservoir as the brakes).
Motive makes a good one (which I own), but I have recently seen a far superior one from BAVAUTO -
http://www.bavauto.com/shop.asp which costs virtually the same but has much nicer features. Look under the brake category and then tools.
It's somewhat faulty reasoning to leave the old stuff in til spring. Brake fluid is hygroscopic meaning it absorbs moisture (even from the air). Leaving it in will give it all winter to attack and corrode the innards of the calipers, lines, master and slave through the winter. If it were me, I'd swap it now. The winter air is typically very dry and so it'll still be very fresh come spring.