Need help understanding

I have been flittering around the idea of LPFM broadcasting for years now.
I think technology has allowed my to rather cheaply do it . I have a few questions about setup.
I am looking at a PCI MAX 3000+ and a 15w half wave sleeve dipole antenna.
What length of coax and what height to get decent broadcast range?
Would it burn up my PC because of the power draw?
I have about a 12 sq mile area that I am in the corner of that would be dream coverage.
Signal repeaters seem like a hassle, and I don't want too strong of a signal, so I can lay low.
What are my options?

Thanks in advance for your replies.

HINTERBART