where is one place where I can purchase the heavier extractor spring and crane o-ring, along with some extra mcfarland gas rings?

cmmginc has their bolt egress kit, this sounds like you are looking for.  you can find it under the specials section

from their site

E.G.R.E.S.S. Bolt Upgrade Kit

New E.G.R.E.S.S. Bolt Upgrade Kit. Enhanced Gas Regulation Extraction/Ejection Supplementing System is low cost bolt upgrade that aids extraction and ejection and provides a superior gas seal. Extractor and ejector springs are chrome silicon which won't take a set and provides added corrosion resistance to standard springs. The single coil gas ring provides more consistent gas pressure than conventional gas ring. The addition of the E-Ring and Mil-Spec Black Extractor Insert assures enhanced extraction performance.

Are you having extraction  and Gas sealing problems?  If not, I wouldn't waste your money fixing what isn't broke.

Just my opinion..  not need for a tantrum or anything.