I don't know if Lowe's sells them, but Dahl makes a "piggy back" valve to do exactly what you want:



Dahl is a well known name and any plumbing wholesaler in your area will stock something similar or order them in for you if you pay cash. If you don't do anything to intentionally pi$$ off the guy at the counter, he'll probably give you contractor pricing on them too.

But, if what you have in your wall looks similar to the example on the left, then I'd just buy another Brasscraft compression stop and replace the cartridge in your old valve with the cartridge from the new valve, thereby fixing the old valve. If that doesn't work, then the seat in the old valve is damaged, and installing a Dahl piggy back valve (or competitor's equivalent) is definitely the way to go.

PS:
New homeowners often don't know this, but on every quarter turn ball valve (like the Dahl piggy back valves shown above) the ball valve is open when the handle is parallel to the direction of flow, and closed when the handle is perpendicular to the direction of flow.