hm... I did Astrophysics last year... this sounds familiar. I'm thinking you should use the mass of the satillite as m1 and the mass of the Earth (google it) as m2. And for r... I'd say use the radius of the Earth as well (google it again). I don't think you would use the r of the satillite because it's so insignificant in comparison to that of the Earth's radius. Not 100% on that though, but at least it's a start!