I'm making this (http://www.knitty.com/ISSUEsummer04/PATTvelvetoblivion.html) sleeping mask, but with a yarn that gets about 7 sts to the inch instead of 4.5. How should I adjust the pattern? I'm thinking if I cast on about 50% more stitches that will be alright, but what about the number of rows? And the increases/decreases?

Any advice would be lovely. TIA

The best way to do it is take their gauge and figure out how many inches in the cast on and the rows. Then you convert that measurement to your stitches per inch.