Should I see a specialist for kidney cancer, or can my regular doctor take care of it?

Absolutely. Kidney cancer typically needs several specialists: 1) urologists are involved in the surgery needed to remove kidney cancers 2) medical oncologists typically prescribe highly specialized drugs to treat them 3) radiation oncologists are involved to give radiation i can't imagine any general medical doctors being qualified to deal with this.
Urologic Oncologist. Urologist shoild always be consulted and treat. Majority of kidney cancers are fairly small and require total or partail kidney removal. An oncologist or radiotherapist may be required in tumor is large + certainly if is spread outside the kidney capsule either locally or metastacised elsewhere in the body. Never herbal or homeopathic treatments.
See an oncologist. I think you should see an oncologist, and not just a regular primary care doctor as kidney cancer management is very complex.