Until you find a new one, you could try using J-B Weld on the old one.

Years ago, I punctured the lower pan on Guderian on the way to work and didn't realize it. Seven quarts of oil on the company parking lot.

Without removing the pan (no gasket immediately available), just cleaning from the outside, I used J-B Weld to patch it until I could find a replacement. At the time I think a new one was $100+. Over the six months it took me to find a used pan, I lost about 2 quarts through the patch. If you can work from the inside, it should work even better.

New is the way to go like greazzer says, but in a pinch if you have to run the car now, try the patch.

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1983 300SD "Guderian"
1987 MR2
2015 Camry
2015 Chevy Spark
2006 Hyundai Tucson