do i need a bigger dish?

[violentj]

hello,been reading a lot in here recently,im building a htpc but cant make up my mind weather to get a dvb-s or a dvb-c card, ive got a sly dish on my house,if i got a dvb-s card and cam would i need to get a differant dish to make use of it, can anything be dycrpted on a normal dish

any ideas which would be the best to go for as is at the mo--ie just get a dvbc-zeta blue-ci for the live cable feed
or get a dvbs-dragon/diable

help im confusing myself here