1999 Mercury Mountaineer Replacement with non OEM?

HI. A mechanic said the condenser has leaked out the coolant and needs replacing. Are there reliable used/rebuilt parts available?OEM Or just go after-market to save cash? Is there a rebuild kit or place to get it done?I am not sure I can do the mechanical replacement of the parts, but with the right helpful hints, I'd try. Also, have been told that the pump should be fine running without the coolant in the system, true or false? Yes in a perfect economy I'd have gotten rid of this thing back in May. But for now, what can anyone recommend? Is there a phrase to search for online for my city's expert installers or supplied PARTS installers? Lost on this one!