[KathieK]

I understand that you are looking at this recruiting effort as a way to attain a financial goal. Perhaps that won't produce the best outcome for your team in the long run.
Recruiting students also means developing a plan for support and retention. Can you financially support the additional students (even with getting the $12K)? Will you have to do additional fundraising to support the expanded team? Do you have enough adult resources so that the team is mentored/supervised properly? Do you have a physical space which will allow that many students to work on team-related projects? Do you have enough assets to allow students to work (tools, computers, etc.) or will they just be hanging out because they can't get to a computer to work on animation or programming? If you plan to travel by bus, will it mean hiring an additional one to go to competitions? Do you have a team organization/structure in place so you don't have chaos?
Unless your goal is to increase the numbers of students getting involved in FIRST, you may want to start looking at alternative sources of funding.
If you decide you want to increase the size of the team, then think about it like a business would. What skills are you lacking that would help the team grow? Do you need someone who can manage the team budget? Talk to your accounting teachers. Do you need someone who can design a killer logo and t-shirts and marketing materials? Talk to the art/graphic arts teachers. Need someone to work on the words for the website/brochures/Chairman's Award submission? Look for someone who has good writing skills. In other words, don't just think about how to attract people by demoing your robot. That may attract people who think they will be joining the team to build it and drive it. And with a larger team, that opportunity might not be there. Target your recruitment efforts.