Try this site and look at the free quilting patterns by manufacturer, maybe you can find a quilt with a similar block and download the pattern.
http://www.fatquartershop.com/freequiltpattern.asp
Also, here's a free site that gives you the directions for over 1600 blocks, you have to click on the names but you could browse through and maybe find something similar as well
http://quiltbus.com/free-Quilt-Blocks.htm