Help please

I just recently got offered a job a couple weeks ago. I'll be working at night while my SO works during the day. The only things is he gets out of work at 5 and I'll be leaving for work at 1:45. We already know we would need a sitter to cover from 1:45-5pm about 4 nights a week for our 5 month old son. During this time my son normally takes about a two hour nap and maybe will eat a bottle. He's a really content baby. And she wouldn't be taking him anywhere. We have WiFi and cable on hand to use as well. What would you charge or be expected to be paid?