I second Christopher T.
It just doesn't sound like you're ready.
First, I'd like to ask perhaps the most important question: how much time do you have???
From the sound of it, you don't have much, and the following post goes on that assumption. I apologise if it's incorrect, and will change my advice if that is the case.
You should not be looking to learn new tricks at this stage. By "should not" I actually mean I think it would be appalling if you tried. You need to perform what you know - not what you can cobble together over the internet in a short amount of time. If you can't put together 15 minutes from the material you have (adapting it to the stage if necessary), cutting and pasting suggestions from other people about how you perform is no better than failing miserably in the spotlight.
And the biggest problem I'm worried about is this. This isn't your show to mess up. This is someone else's show, who has to follow you no matter what you do - and who has given you an opportunity. If you can do it, by all means take it, but if you can't, then it's his show you're performing at. If he's kind enough to offer you a slot at his show, chances are, he will be kind enough to do so later in time, as well, if you're not ready.