Jim,
Most large Napa Auto Parts stores will be able to match the compressor. Sometimes it takes a day or so to order the right one, but it is usually no problem buying a replacement.
One word of caution though, be sure to check that the compressor clutch is getting 12 volts and that it has a good ground. Low voltage to the clutch wiring or a poor ground will give you the same symptoms. So if you have either one of these conditions, a new compressor will not solve your problems.
Gerald