You can do it! And it won't take you that long. I'm going to make a small suggestion. Learn to read the bass clef on a keyboard - maybe do that first. Keyboard is set up so that it's easy to remember where one's fingers are in relationship to the clef. You put your left thumb on middle C, you get a beginner's book that shows middle C on the bass clef and voilá! first five notes are a piece of cake. All the rest of the notes will magically become clear.
Middle C on your bass is your G string, 5th fret, and the F that corresponds to where your pinky finger ends on the keyboard is your D string, 3rd fret - just to give you the comparable range.
Here's a short lesson for the keyboard (it's just so easy on a keyboard):
http://www.piano-play-it.com/read-piano-notes.html
Here's the bass clef tied to the bass strings:
http://www.guitarnoise.com/images/help/128/2.gif
Here's a game to test your new knowledge:
http://courses.wcupa.edu/frichmon/us...s/bcnotes.html
Naturally, you're going to feel nervous at first, trying to use this new skill - but I promise you can be doing the basics by next week (those new charts you're trying to read really are directing you to play bass in a way very similar to what you've been doing - you'll learn to pick out the main notes on the clef very quickly and translate that into what you do, already, very well).
No better time and place to learn it - that's what pep band is for!