you could add another yarn in with it. i do that all the time. i really like bernat's soft boucle. or try larger needles and make a gage sample. or try loosing up your tension on the yarn, that might help.

good luck and keep up posted.

Thanks Knitcrazy. I've now just about got enough gauge squares to make an afghan. It's driving me nuts.

I've decided to use another yarn with it but currently working out which thickness. Don't want to go larger than 10mm needles - I find the big ones really uncomfortable to use and I don't want to lose the thickness. We're just starting winter down here.

I'm making it as a present for my daughter and figured she may as well look glamorous sitting at her desk studying for her uni exams. She's too far away to hug personally.
Actually, the Bernat site lists it as suitable for Beginners. I found the second row (increase in every stitch) incredibly difficult. There wasn't enough "give" to push the stitches down the needle, no matter how loosely I tried to knit. I ended up casting on with the 9mm/10mm needles, knitting the 1st and 2nd rows with 15mm needles, and then went back to the smaller needles.