My A/C is to old and they don't make replacement capacitors?

Run, don't walk about from any shop that tells you this. If the ratings match you can use any brand of capacitor, it should even be fairly easy to find on that matches close to the original size and shape. Ebay and other online vendors will be the cheapest, in the town where I live capacitors sell for 6 to 8 times more than they do online for a $5 online capacitor will sell for $30+ here.