Hey Jake,
In short you want a full on HD multi-camera studio with all the cabling and mixing and streaming hardware/software for $25,000?
Sorry mate, but you need a miracle (This is me being very gentle).
Either ask for more money or reduce your expectations.
Since you already have a powerful Mac I am assuming that you maybe also have a camera or two? It would be good to know what other equipment you have?
But you should consider starting with just 1 camera that can do the live streaming - something like a HDV camera should be fine (Canon, JVC, Panasonic, Sony Z or EX model). If you can afford it, buy two cameras and use the second for inserts after the service into the main programme.
Alternatively, ask for more money and buy a Newtek Tri-Caster with whatever cameras that you can afford to fit the budget.
Good Luck
All the Best
Mads
London, UK
Mac Million Ltd. - HD Production & Editing
Please watch our Showreel here:
http://reels.creativecow.net/film/1145
Blog:
http://macmillionltd.blogspot.com