maybe this was discussed and i missed it. her insurance needs to get the car back to what it was before she hit you. that includes mechanically. do you have a shop for the bodywork? they should have a mechanic in house or mobile they use. have you talked to her company and told them it does't run right since she hit you? could be a pinched fuel line. have it towed if you need to, but get it in a shop, and have them give the estimate FOR EVERYTHING to her company and get it fixed
why does everyone want cash up front for a job an insurance company is paying for?