When I was D2 last season I started the with basic, struggled to fill seats and quickly switched to advance for about $7-8000 more a week. I noticed an immediate spike in attendence that was far greater than the extra cost.
There's no specific formula out there to tell you what you gain exactly but I think you'll find that it's well worth it. My theoty is that the BB gods didn't put PR managers into the staff calculations without them being worthwhile investments at some point in your team's growth.