You need to be careful which shifters you get as it depends on the derailleurs you want to use. Campag and SRAM use twice the cable pull of Shimano if I remember rightly so you need to keep yourself within one of those two camps.
RE the bottom bracket, you'll need to have a look at what you have to play with. However, it's probably a cartridge shimano bottom bracket judging by the rest of the gear on it, so you'll want one of these. You can get ones that are attached to handles already but the separate ones allow you to use bigger or smaller spanners.
You need to be careful which shifters you get as it depends on the derailleurs you want to use. Campag and SRAM use twice the cable pull of Shimano if I remember rightly so you need to keep yourself within one of those two camps.
RE the bottom bracket, you'll need to have a look at what you have to play with. However, it's probably a cartridge shimano bottom bracket judging by the rest of the gear on it, so you'll want one of these. You can get ones that are attached to handles already but the separate ones allow you to use bigger or smaller spanners.