just find some wav drum loops on the web and use them, or make your own, there should be some nice one's on the web, do a search, google...
you can also load a "loop" into FL and use it with the pattern section, it works very well, you'll need to adjust the sequence length most likely though, 4-4 to 4-8 or 4-16 etc...
you don't need the Cd loops, just search, there out there by the thousands, but, some good "wav" some bad "mp3" make sure of the bit rate your loading, mp3 is pretty much a waste imho...
FL has a good selection of single drum hits that come with it, the loops are techno dance and not really rock loops, but you can surely make a rock loop and rip it the incert the loop back into Fruity, and twist some more, rip again, over and over, back and forth, you get what i mean...
there was an ftp with FL samples that was hosted by someone here but last time i tried to connect it was down, like for a month, and i haven't tried since...
ask for drum loop/sample links might help...