Turns out the workshop doesn't have stainless steel cutting tools, looks like I'll be buying new pistons. Thanks for the input everyone.

They are only Tipped tools nothing special,Not much of a workshop.

The workshop only works with mild steel and aluminium. Anyway i got a fully working used caliper for $30. Just wanted to know, when cleaning n greasing everything like the pins and bolts and all that, is red rubber grease fine or should i be using something else?

Red rubber grease !
Surely the clue for it's use is in the name ? (just ignore the "red" bit)
Use high temp anti- seize paste on brake mechanicals.

Is that fine for all the caliper parts including lubing the piston and seals and boots?

Use rubber grease or brake fluid on seals and/or boots at installation
Use copperslip or similar on the fixings/pins/back of the pads.

When the piston is pushed back in it should slide in nice and easy if it doesnt take it out and clean behind seals again.get a small screw driver in the lips where the seals go and make sure u have got all the salt and road grime out of there. I also use a hard tooth brust and some petrol .cleaning the caliper properly is imperative mate otherwise your wasting ur time.its not hard just be thourough .

Okay thanks guys, will get to sorting it out soon. I noticed the caliper had nc35 written on it, although I have a nc30 bike. Are the calipers the same? They seem to look the same. Its a rear caliper btw.

If they look the same I would say yes. To be sure measure the fixing centers or even try it on bike before you start to clean it. If it were me I would clean it first and fit the pistons then rub it down and paint it while its off. But I am ocd :-).

Haha okay cool, will do, thanks. Btw can someone tell me where the the flasher relay is mounted?