Plexiglass engraving

I have the same issue, I want to have my plexi etched but have zero idea other than taking it to a shop and getting it done.  I don't know how to get a symbol. or font to a suitable size on my computer in order to print it out to make a stencil.  Any ideas?

you should be able to take it in on a disk, and they can pop it in there computer and resize the picture, and the computer will have it engrave to those specs.   

My fiance's mother owns a screen print/embroidery shop, this is how they do much of there products,  very similiar in a way.

Thanks for the help guys. I went to a local engraving shop yesterday they laser engrave cast acrylic. I took a spare piece of there stuff home last night and shined a led through it and it works great so Im going to be getting them to do it.  I only have one other problem, I was sanding down my piece last night and I tried to fit it back on to the trunk lid and noticed it doesnt fit anymore,     Sooooo I need a little advice one of the corners is pulled back and glassed into place. Apparently when I stretched the fleece I pulled it backwards so now the top sticks out about an inch or so. So if I have to cut that corner off what can I rebuild it with. I thought about duraglass, I thought about fiberglass down then duraglass on top. I thought about resin mixed with cabosil or something like that. what do you guys think would be best?

If your confused I can post a pic not of my project but a similar one and show you the area that might need to be cut.