Hemangiopericytoma: Looking for Your Opinion

After finding a small lump on the back of my gorgeous dog Lola's leg (she is a chihuahua mix), a needle extraction revealed it is likely
Hemangiopericytoma.

This has been such a tough decision process as Lola is in excellent health and her breed typically has a 16 year life expectancy, but she is 13 1/2 now.

The vet has recommended we remove the lump and do a complete biopsy to confirm diagnosis. If it's what she expects my choices are:

• Let it grow back (which it will) and love her until it becomes uncomfortable for her, then put her to sleep
• Radiation treatment, which will involve treatment M-F for 3 1/2 weeks. The doctor is recommending this course of action as dogs tolerate it very well and for Lola's situation, since it's on her leg, feels it has a high rate of success.
• Amputation

I'm just so torn. I love her so much, and need to put her first so in my
heart I feel that the surgery and radiation would be the best option. But in my head, I think about the fact I'm a single woman and finances are an issue, this course of action will cost between $7-10k and Lola is nearly 14, so even in best case scenario she will have another 2-4 years. But I also don't think I can sit here and watch that thing grow until it cripples her and then put her to sleep.

If you or anyone else has faced this kind of situation I would greatly
appreciate hearing from you. Many thanks.