Gateway computer hard drive?

i have a gateway mx6030 laptop and the hard drive crashed having some bad sectors. my question is looking at the web searching for a new hard drive, i noticed sleds and caddys offered for this drive, do i need one of these? my second question is the computer came with a 60G drive, either a fujitsu mht2060at or a hitachi 60gic25no60atmr04-omlch69555 drive. do i have to use the same size drive or can i get a larger drive say and 80g, 100g or 160g drive and what is a reliable brand name and model number?