As a non-profit, you *may* qualify for Google grants which gets you $10,000.00 per month in free online advertising in the Google AdWords program. Not to be sniffed at. You may not even be able to spend it all.

If you do qualify, then find someone who can spend that money wisely for you who is interested in your cause and will likely work pro bono, and show you the return it gets you in a defined metric, like donations received or whatever.

If you're really smart about this you'll also get that party to commit to mentor your marketing person as part of the program, so you can take that knowledge in-house as well.

You need to know that what you spend comes back several times over (this is what I do for AdWords clients).

I'd be willing to help get you started and see how it goes if you do qualify for the grant.

Good luck!