How exactly to extract information base 10 from a PGP RSA key pair?
You can use the Web tool pgpdump, available at this address http://www.pgpdump.net/ or the same tool ( http://www.mew.org/~kazu/proj/pgpdump/en/)  to install on your pc. 
This latter is to use if you are poking with your real secret key. 

At the moment I don't remember if the tool outputs in hex or dec, but you can easily convert to your favourite Base using python or pari/gp or whatever mathematical tool you love more.