🚀 go-pugleaf

Greetings, I have a simple question that I'm sure someone can answer.
I'm building a simple circuit that contains a 555 IC timer chip.

                        Vcc
                         |__________
                         |          |
                         /        __|__
  R = resistor         (R1)    __|_____|__
  C = capacitor          \____|  4     8  |  
                         |    |7          | (Output)     __    __
                         /    |          3|---------> __|  |__|  |__
                       (R2)   |   (555)   |
                         \____|   TIMER   |
                         | +  |2          |
                         | |__|           |
                         |    |6    1    5|---> ???
                        -+-   |_____+_____|
                       (C1)       __|__
                        -+-        ---
                       __|__       GND 
                        ---
                        GND 

    Where Vcc = 5 volts      Pin 1 = ground   Pin 5 = control voltage
      Current = 125 mA           2 = trigger      6 = threshold
                                 3 = output       7 = discharge
                                 4 = reset        8 = + Vcc

         1) How do I find the values for R1, R2, and C1?  Is there a formula
            [ie. C1 (R1 + R2)...]

         2) Can I replace R2 with a potentiometer so I can variate the
            output timing (ie. speed it up or slow it down).

         3) What does pin #5 get hooked up to?

      BTW, I'm trying to hack together a rapid fire device for my joystick
      with my little knowlege of this type of circuit.

      I figured I can replace R2 with a pot. to be able to acomplish the
      rapid fire action.

       I would apprciate anybody with knowlege of this kind of stuff can
       help me out.  I'm stumped right here...please email so we don't
       offend anyone.
                                         Thankyou.
                                              
PS, sorry if this is not the appropriate newsgroup to post in.