suspension and brake problems.

i left my house the other day, i get down the street and my brake pedal went straight to the floor(no pressure). i took off my front wheel to find some fluid dripping off the spindle fluid seems to be coming out right where there it some rubber around the piston. i also found that one of the bolts or end caps(looks like a 1- 1 1/2 inch hex nut) on the upper control arm is missing on the side where it connects to the body. theres just a small bar going through a bigger hole in the control arm where the bushing or whatever should be there
1. where can i get a new brake caliper for the granada disk brakes and how much does it cost, or can i rebuild the one i have?
2. do i need a new control arm or can i buy whatever is supposed to be there and if i can, what is supposed to keep it from coming back off?

thanks, noah

how do i post a picture?

i can get a rebuilt caliper for 15 dollers so i think ille save myself the hassle and go with that. i guess ill get the rebuild kit for the con arm
thanks