Individual parts for your pump (bearings, seal, gaskets, etc.) will cost about $50. A complete rebuild kit with new shaft, bearings, seals, gaskets, cover plate etc. is $177.40. This link takes you to the specific parts page at Westerbeke.
If you take the pump in to a shop it should take 1 hour labor at most for the repair if you supply the parts. If they try to charge more they are robbing you.