DC2 brakes problem

Hi, I'm having an issue with my brakes. My rear left wheel was making this really loud noise when reversing. Then i started hearing this tingy noise when I was driving forward. Thought it was the brakes and rotors so went for a full change then I noticed this...

http://i50.tinypic.com/5yst50.jpg

Seems as though this thing that's pushing the brake pads in aren't retracting. Does anyone know how I can fix this?

I'm also looking for some bolt replacement, the one that's used to screw the rotor on. Anyone know where I can get this?

have you sprayed anything on them? or is thatbrake fluid leaking from what i can see u havnt disconected the handbrake cable wich is a must an you have to turn the pisto clockwise whilst pushing an the bolts arent that neccesary as the centre bore or the rotor is located by the hub and the wheelnut hold the rotor against the hub

Seem that the piston is leaking, and the sound is because the piston it's not retracting.

All that liquid is just lubricant so don't think it's leaking. Is it as easy as winding the piston back, put everything back on and see if it retracts?

you need to "wind" it backwards into the piston housing. Back off the handbrake and open the brake fluid reservoir - and wind it in with a large flathead screwdriver or flat edged tool (counter clockwise i think ?!). Rotate SLOWLY as to avoid tearing the seal around the piston. do not rotate until flush with the housing , let it sit alittle above.
Monitor the brake fluid level as it may spill out of the reservoir , remove fluid if needed close up put brakes back together and wheel on and go for a ride.

Bens right, but i think its clockwise? lol dont even remember. If you have some brake grease or general lube ( preferable not a spray as they dry quicker ), apply a light amount on the outer edge of the piston so that it doesnt catch on the rubber seal. Then when done if the brake fluid has overflowed make sure you put the cap on and pump the brakes for abit to push the pistons back out to their ready position. Then remove any excess fluid to bring it to the max line. Also remember to wash off any excessive brake fluid with water as the brake fluid will eat the paint if left there too long.

Piston must be winded back clockwise. Make sure you line up the cross on the piston so that the pads sit flush or you'll have uneven wear on the pads.

At the moment with everything reassembled the loud noise when reversing is gone but there's still a loudish noise when going forward. Kinda like something grinding on the discs. Wonder if this is normal for new brake discs and pads?