Gina,
Dont panic!!! I have an authentic italian red sauce recipe that I got from a little old lady from Cicily(sp). You can use either your own tomatoes or canned to make it!! I have tried about five different tomatoes over the years and each one is FANTASTIC!! Here ya go:

RED SAUCE:
4 CANS TOMATO SAUCE
2 CANS TOMATO PUREE (OR USE YOUR OWN TOMATOES JUST ADD 4 CUPS OF YOUR PUREE)
2 CANS TOMATO PASTE
1 CUP PARMESAN CHEESE
1 ONION
2 TBSNS ITALIAN SEASONINGS (OR CREATE YOUR OWN)
2 TBSPNS SUGAR
1 CLOVE OR GARLIC CRUSHED
1 TSP OF SALT

IN A LARGE POT ( I use cast iron) place sauce, puree and paste add sugar and salt. Add five cups of water stir well. In a blender add one cup of water, cheese,seasonings and blend until smooth. Add to tomato mixture and stir well. Add crushed garlic and stir. Bring to a boil and then simmer on very low heat for 5-6 hours. This recipe makes four quarts. So you can increase to use your 15lbs of tomatoes!!

TRY IT YOU WILL LOVE IT!!!