seriously? hmmm...let me put my thinking cap on...

idea 1: get a time machine, go back in time and work harder so that you have more than 1 project to show for your undergraduate career.

idea 2: submit very thin portfolio, less is more!

idea 3: donate large sum of money to university to build library, then apply to graduate school.

ok, enough jokes...but this is sort of like posting "I"m swimming across the english channel, but don't know how to swim...any suggestions?"

yes, I suggest you learn to swim. or in your case, either rework early projects that you're not happy with until you are happy with them, or attend a summer architecture program at the university of your choice, thereby creating additional projects for your portfolio.

You don't say when you're applying to g school...I hope you're thinking of the 2012-13 academic year.

I'm applying for 2011-2012, and I only had two projects from undergrad that I used for my portfolio (2/5). One of the five was from a program abroad in France I participated in the summer after I graduated, the other two were competitions I did that were posted on Bustler. My suggestion is to do just that, keep an eye out for competitions that you're interested in, do maybe one a month (more or less depending on your interest in the premise and also your confidence in your concepts), and build up a portfolio that you can use for 2012-2013.

Also concerning undergrad, i doubt your other projects are no good (as jcarch might think) but that you're only picking cream of the crop. I was in the same boat - don't fret. Reworking previous projects is always a good idea, just one that I didn't have time for.

Good Luck!