Thiss may be a picture of the pattern:
http://www.ebay.ie/itm/James-C-Brett...-/130667767891
Try knitting a gauge swatch in your yarn and needles (this may be best done in the aran pattern). See how many stitches you get per inch and figure out how many sts it would then take for a 30" bust (or ~15" across the front or back). From there you can figure out whether it would be better to try a smaller size needle or to alter the pattern to make it smaller.