So it sounds like you want to do sports stadium type graphics in a high school gym type environment and budget, using two projector screens. There are a lot of ways to do something like this. There are fewer ways to do it successfully on a low budget. I think the key is to start out modestly; Just use the screens as scoreboards and stats boards, and to play a team intro piece for each team, maybe also the National Anthem.
The basic system for this would require some kind of laptop computer to generate the stats screens, and to play back media files, a device to convert the laptop video output to whatever the projectors might need as their standard, and a very basic video switcher, to cleanly feed that laptop and other, future sources, to the projectors and make pleasant transitions like fades and dissolves.
The stats screens could be done with something as simple as Powerpoint or photoshop or windows paint, but fast updates and ease of use would tend to demand actual “Character Generator” graphics programs, preferably one built for sports use, with templates that let you quickly build new screens and update old ones.
So my first suggestion is to find a modest-priced “CG” app that plays on the hardware you already have.
You will see ads on this site for a box called the Newtek Tricaster: this is an all-in-one solution that could certainly do the job for you, but it may be overkill at this stage. See how far you can go with just the character generator first. There are numerous choices out there, in the under-a-grand price range , one is called Cayman Graphics, look it up and see if that’s about what you want, or if you need more or less “firepower”.
How will you feed the projectors a signal? VGA cable, or long coaxial video cable? Most laptops don’t output a TV video signal directly:they tend to need an attached converter box, called a scan converter, to turn VGA signals into composite or component Video. Scan converters sell as low as 90 bucks or as high as 7 grand and up, depending on features needed.
While a video switcher isn’t strictly necessary to start with, it lets you operate in a more classy way, by being able to smoothly fade out the screens while you make updates to your scores, or call up a video file to play. Without the switcher, the gym is going to see what your laptop screen is doing at all times, and this can be distracting. There are cheap switchers under a grand that will work for this.
There are also laptop apps like BoinxTV that might be fun, cheap way to get started in this area without committing a lot of money.
Try shopping at these web sites for the things you need:
Markertek
B&H photo-Video
Fullcompass.com
TigerDirect.com (for scan converters)
Good luck!