New to CRM have a questions about Direct mailers

New to CRM have a questions about Direct mailers

I do most of my marketing via Direct Mailers to companies.
How would you suggest I do the following:

1. I need to mail a brochure once a month to potential customers.
2. If they buy i take them off the mailing list, and don't mail them again.
3. If they haven't i continue to send them a brochure.

I would like to use the "Print Mailing Labels" feature available.
This way once a month I print the labels of the companies that need to receive a brochure.

Do you have any suggestions on doing this?

Thank you,
Camie