How to use my HDMI projector wirelessly or via bluetooth?

I'm a middle school teacher, and my problem is that the HDMI projector hook up is in the very corner of my classroom. This forces me to put my desktop computer in this corner of my classroom, and I have to run back and forth from the board to the computer every time I'm projecting something on the board. It really makes it difficult to interact with my students.

I have access to the following devices:

- HDMI In-Focus Projector with no wireless features (projector is connected to the ceiling with the cable running through the wall to the corner of my classroom where my desktop is)
- Dell desktop computer
- MacBook Pro
- iPad
- iPhone

For now, I'm using a "remote mouse" app on my iPad to use the iPad as a tracking pad for my PC. Basically, I look at the PC screen being projected on the board, and from there, I use the iPad as my mouse. This allows me to roam freely around the classroom while controlling the PC.

I would love to be able to project my MacBook or iPad on the board (instead of the sluggish PC that my school provides) without having to be hooked up to the HDMI cable in the corner of my classroom.

Is there any way to do this? I'm willing to invest in an adaptor, cable, etc. In order to do this.

P.S. I looked into the Apple TV device, but it is best used for small at-home networks and can't handle our school's more complex network.

You could buy a HDMI wireless transmitter, but their not cheap.

Heres an example of one.

http://www.buy.com/prod/nyrius-aries-home-hdmi-digital-wireless-transmitter-system-nwhd300/230237374.html?listingId=212267668

Another possible solution could perhaps be a semi-permanent cable? If you buy a cable thats always hooked in to the projector and thats long enough to put in a nice way and then also have enough extra lenght over to reach the computer/device.
Thats how we did it in our school atleast. We had a cable running across the roof and down next to the board where we just put the computer (or connected it to the desktop we had there)