So I'm the sound engineer and somewhat knowledgeable in the video aspect, I'm not quite sure what I need to accomplish this task.

Essentially we have 3 tvs around the venue, 2 in the main stage area and one by our Cafe bar. There is installed coax already as they are hooked up to cable. What we want to do is hook up our computer (either via dvi or vga) to play slides of our upcoming shows and things like that. What do we need to do this? There is a tight budget right now so the lower the cost the better. Running all new cable of hdmi or something isn't really an option right now.

Any help pointing me in the right direction would be awesome!