PM me, i know how to build basses (Neck Thru, Bolt On, Set IN, etc..)
here is a run down of the stuff...
tuning machines - they range from like 10-20(each) for decent tuners, but remember the cheaper the tuner is, the less your bass will stay in tune... here is a site to get tuners
http://www.stewmac.com/shop/Tuners/Bass_tuners.htmlStrings - i always recommend Ernie Ball, depending on your nut size (i'm talking about the basses nut) depends on your string size... going to big of a gauge will make your string get stuck in the nut and when you tune, the nut will break off the bass (i know from experience), and going to small of a gauge will make the string shift around in the nut and will not keep in tune for long. here are some strings...
Musicians FriendFlatwound are for fretless, Steel makes the bass sound like crap, go for the slinky (different types of slinky have different gauges
electronics - electronics can mean a lot. the pickups could still be good, but the inner electronics might be damaged. check out the inner electronics and make sure everything is soldered, if something is hanging off, get a schematic of how the bass is set up (i need to know more about the bass, and i'll get it for you) and fix it. now if it is the pickups then get new ones... i suggest Bartolini, and i highly recommend that you do NOT get EMG's...
faceplate - do you mean "pickguard"? if you do, here is a site with standard pickgaurs
http://www.stewmac.com/shop/Pickguards.htmlif you bass is different, tell me what kind and i'll find where you can get a pickgaurd for it. ***there is a 90% chance that the pickguard is connected to your electronics, be careful when you take it off***
bridge - this is by far the hardest thing to get, you need to know your string spacing. here are some STANDARD bridges
http://www.stewmac.com/shop/Bridges,_tailpieces/Bass_bridges.htmlyour bass might be different, PM and i will guide you thru the process of getting a new bridge...
there is more that IS wrong with your bass, if it gathered a crap load of dust, that probably means it hasn't had a set-up...
you probably need to adjust the truss rod.
you need a intonation and action adjustment (it doesn't matter if the bridge is new or old)
if you have anymore questions PM, i can help you faster that way...
EDIT: first make sure that you NEED the stuff BEFORE you buy it, many things can be fixed easily