You should easily be able to fill up 5 minutes with two effects. If you can't, youre rushing your effects and not taking your time with each one. Take the time with the closer to make sure everyone realizes how fair it's been. Interact with the audience. Have fun.
That said, think about the way you've routined what you've done. You produce a silk, then put it aside and do a cell phone prediction effect? Hmmm... Where's the logic here? This is just magic for the sake of magic. There's no flow. Think about it.
I would say drop that first trick all together. Only do the second one; the cell phone prediction. And really take your time with it. Hype it up, talk about whats hapenning. Have numbers thought of, decks shuffled, really emphasize the fairness or it. No trick is going to be seriously magical if you only spend a few seconds on it. Take the time to invite everyone up, introduce them, joke around with them and ineract.
Remember, you're not only a magician, youre an entertainer. People want to feel a connection with you, and they want to walk out of a show smiling. Thats it. Take the time to get to know them. Work on your patter and have fun. A 5 minute show to me, sounds like one effect. That's it. You do one solid thing and youre out. If you really want more then one, do a quick opener that ties in with the finally. Produce the card box or something.
Those are just my thoughts though...