Help Leonardo replace the engine head gasket and return to work

I make my living with my delivery van. 7 weeks ago the engine head gasket failed, and the mechanic says the repair will cost $450. Without the vehicle I earn nothing. I have been borrowing from friends to pay rent, and now I have run out of people to ask. I support my two daughters and my mother. Before the breakdown I worked nine hours a day, six days a week. I have been offered extra shifts for the next six months if I can just get the vehicle working. I have a written estimate from a certified mechanic and will upload it here. All money will go toward the parts and labor on the estimate, with a small amount for road tax and insurance renewal. Where the $450 goes: • engine head gasket replacement (parts): $300 • Labor charges: $50 • Road tax and insurance renewal: $65 • Towing and inspection: $35 Please ask me anything in the questions section. I'll answer honestly and quickly. - Leonardo