just new here... found it on google, and i think i am in heaven

i have been brewing my own for 7 years, but never kegged. i was recently given a little horseshoe bar that used to be in a venue, it has a hole in the bench where a tap can go (i believe), and i figured i would tap it.
my questions are:
1. what do i require in order to have a keg set up at home? i honestly have no idea how its all done.
2. if i buy a homebrew keg, will i be able to interchange the lines (if i run out of HB) with a "normal" keg i could buy from a shop. e.g, a keg of tooheys new or whichever.
basically, can i use a HB keg, then a normal one? or is there a better way to do it? 2 taps perhaps?
3. refrigeration. any tips on if i should use the fridge i currently have next to the bar (a normal 300 ltr), or should i buy a little bar fridge, or is there a specific item i should look at?
sorry for such a long first post...but any help/advice will be much appreciated
thanks