Vet Fees for life saving surgery

My young cat Tiggy went missing for 6 days and arrived home in the middle of the night starving and with really bad injuries. We got an emergency appointment for the following morning and scans showed a broken pelvis suggesting she has been hit by a car. She has been referred to a specialist hospital leaHurst where they are going to perform life saving surgery. My heart has been broken since the day she went missing and when she came home I thought all our dreams had come true and she just had a sore leg but finding out she needs surgery is so scary and we are so worried. We have pet insurance but this only covers up to £2,500 worth of vet bills and the estimated cost is between £4000 and £60000 and this doesn't include the bill from the first vets who referred Tiggy. Please help us raise the money to pay the outstanding vet bill between £1500 and £3500. We are broken hearted and so are our 2 little boys. I am a supply teacher and due to covid there has been little to no work yet and we just don't have the funds or any spare money each month at the moment. We appreciate any help given. UPDATE: Tiggy is doing well but surgery will not commence until Friday due to the severity and careful planning is needed. We are overwhelmed at the kindness shown by people you are all amazing. We have made the extra £1500 to the pet insurance but the bill is looking likely to be close to £6000 after speaking to the vet her 3d scans and the placement of the fractures attaching to her spine and hip joints. We appreciate all your help and I have adjusted the amount on GoFundMe but we will set up a payment plan for anything outstanding. Thank you all so much.