1997 civic ex ported and polished head

i have a 1997 civic ex and i want to buy a head and get it ported and polished because i cant be without my car for that long...
What would be a good price on a good head from the junkyard or a site and what would i tell the people to do who are porting and polishing the head?? One more thing...Would it be a good investment??? Would i have to do anything else along with that?? here is my list of current mods

header
full exhaust
plugs and wires
cai
msd ign
msd blaster
msd distr
short shift