Adobe is not a program, it is a company, There are several programs sold by Adobe, but I assume you are using Illustrator, since that's where you are.
You can just Save As with any file to make an EPS. If you are using any version but Illustrator 11 (aka Illustrator CS), then you can choose the version for the EPS file when you save it. You probably want to save as a versio 8 or earlier file.
If you are using Illustrator 11, then you must Export your file asn Illustrator Legacy EPS.
WHen working with sign making, there are some things to do to prepare the file:
* Convert all text to outlines,
* Make sure there are no raster effects in the file (drop shadows, glows, fethering, blurring, etc.),
* Only use solid colours for fills, no gradients,
* Do not stroke anything. It you want to make something look like it has an outline you need to expand (Object > Expand) any stroke applied to that shape.
There are other considerations. The sign shop is far more aware of what they can do than I am, and they likely have professionals working there who have seen it all and can alert you to any hazzards in your design.