How do I find index of refraction if I have the incident angle and refraction angle?

Use snell's law. You have to have both indexes of refraction.

what do you mean by both indexes of refection? I put a lazer beam through water.

On side is air, one side is water.

take a look at Snell's Law

N1 SinTheta1=N2 SinTheta2 right?

and i`m trying to find n2 right?

Yes, if N2 is index of water.

Thanks so much :)