Some of the factors any manager will consider besides your
technical ability with any language are:
Can you work independently?
How much guidence do you require for your work?
How dependable are you? Can your manager rely on
you to keep the commitments you make?
Can you communicate your ideas to others,
orally and with witten documents?
Do you make your manager's job easier or harder?
For a given area, find out what others with similar
abilities are making. You should expect the same.
Salary often results from your ability to present your skills,
both technical and non-technical, to whomever
is doing the interviewing. There is much information
on the web on how to do these things. Any of the job
search sites, like monster.com, have a lot of good stuff.