For gauge I'm supposed to have 26 stitches and 40 rows per 4 inches. I knitted a swatch in the pattern on 3mm needles as suggested.
However, I've got 33 st per 4 inches and 23 rows? Apparently row gauge is important for this - is my yarn too chunky? Going up a needle size will probably fix my stitches per 4 inches (last time I went up a whole needle size and got the right stitch gauge - I think I'll probably try knitting a swatch with 4mm needles to see how I go.) However, if I go up a needle size, I'm going to have even less rows per 4 inches won't I? Should I just not worry about the row gauge?
Are you sure you're counting the rows right? It sounds like you need a couple sizes larger on the needles for the stitches. Try that, then wash and dry the swatch like you will the sweater; you could stretch it a little wider which will take up the length. The row gauge might not be that critical, you can probably fudge it, but that's if you were getting much closer to the gauge. Looking through the projects on ravelry, many knitters had trouble with the gauge, though they were getting something like 36 rows.