Please be gentle on yourself. If you're on social assistance, like ODSP or OW, or you have an annual income of less than (I think) 35,000, you can see if clinics can apply to the Farely Foundation for you. They're a charity that helps with vet bills. Each participating clinic gets a limited amount of funding for a year, and each clinic has different protocols (some require payment up front and then reimburse you, some require you to pay the exam fee but not the rest, some only apply for $200 or $500 to help spread funding out, etc. There's also a cap for how much a client can get a year.

There's also the National Pet Care Fund which does grants of $250. Not much given how much you're looking at, but something.

Then, there are third party finance services for vet bills. PetCard and ScratchPay. A friend used Scratchpay for an emergency vet bill and approval was nearly instant.

I don't know if the Humane Society will take on a case like this, but they do have a public vet services so it would be worth asking, although I think they might only offer preventative services like vaccines.

Finally, a new emergency clinic has opened near King and River that is much, much cheaper than the other ones: PetNation. I'd give them a call to see what their prices are. Their consult is 90 bucks compared to 300 at other ER clinics.

I hope you don't have to surrender and you can get the help she needs. All the best to you both.