Gain parameters of a differential amplifier

I realize that I did not understand this properly and gave nonsense information:

Now the difference of inputs is 0.0075 volts Ther output is in the range 0-1 volts I have calculated that the gain should be 130.

Now, I need to find R1 and R2, so as to get this gain. What formula should I be using?

Cheers, D

Ok, I see the following formula:

V(out) = R2/R1 * (V2 - V1)

So, R2/R1 = V(out)/(V2-V1) = 1.0 / 0.0075 which is approximately 1300, which is my gain value...

So R2/R1 is the gain value in this amplifier???