Generally, refinishing a pistol like yours ruins any collector value so you have to determine if it's a pistol that you want to keep and shoot (cost-benefit analysis). If you're planning on selling it, you'll probably get more for it than if you spent $$$ refinishing (sell for $$$$, deduct cost of refinishing $$$ = $, maybe sell it as is for $$).
Is the bore rusty as well? If so, don't waste your time or $$$ refinishing. Turnbull can work wonders on a pistol, but it'll cost fairly big bucks. Colt pocket autos aren't exactly plentiful, but at any major gun show you'll see more than a few for sale.
If you just want to scrub off the rust and keep it from rusting some more, try soaking it in a good gun oil for a day or so, then gently cleaning with one of those stainless steel wool balls.
If it has sentimental value, spend the $$$ if you want.
My $0.02