You said she only sees crosdressers now and that you go twice a month, so put 2 and 2 together and got 5.
You also said she advertisers on a crossdressing site but then say you have no idea which one, maybe you could ask her on your next visit
She obviously wants the business or she wouldn’t advertise so don’t see the problem with you sharing where she advertises or her number etc given that is what this site was set up for