Go to a janitorial supply contractor (look it up in the 'yaller pages).
That would be your best bet.
Red stains are the WORST type to get out. There are a couple brands
that are specifically for red stains, that is what you want.
If you absolutely cannot find red stain remover, you may want to try
your luck with the "Oxyclean" type products which is essentially diluted
wood bleach. Most of their claims are bullshit, because that shit DOES
take the color out of carpeting. The key to it's use is clean, then
rinse with water, and put a high powered fan on it to dry the carpet as
quickly as possible (retards the formation of mildew, which can start in
wet carpet in three to four hours).
A third option would be using "Heavy Duty Purple Cleaner". This is a
butyl based product that kicks ass. A dealer buddy of mine uses one of
my carpet cleaning machines for prepping his cars, and when the stains
are tough (especially oil based), butyl cleaners work well. Use gloves.
Use at no more than 1/2 strength. Rinse with water. Dry with fan.
DBT
-professional advice at no charge
