releveling a back yard

I have been asked to relevel a back yard. When it warms up she would like the grass killed off and it to be releveled. I have never done anything like this but I'm not afraid of a challenge. I guess my question is how much do I charger her? It is a75x75 ft square (probably more like a 50x50 tho). Its had a few low spots and would probably need 10-15 yards of soil. Then reseed they yard. How do I kill the grass? Round up?

My brother just had this done last year. The use an everything killer. Takes 2 or 3 treatments to work. They then boxbladed the yard till it was smooth. Then put down sod. They did not add soil they just took down the high spots and put it in the low spots. $500 for yard leveling and sod was $800. Find a Farm and Home place to get the killer. It will be cheaper and better.