We have just a couple of these pretty plants out back. The tallest is about three feet and the blooms reminded me of pictures I saw of "golden columbine" that I saw on the botany photo of the day...but they are a little different.
Yep! It's a columbine. The flowers can take many shapes, but all are still basically similar. Try the linc below. I just googled columbine and looked for pictures. http://www.bing.com/images/search?q=columbine+flowers&qpvt=columbine+flowers&FORM=IGRE#x0y1726
The common name for these in the UK is "Grannies Bonnets" due to their shape. They grow and spread like weeds here, and I love them. Typical "country cottage garden" flower and very pretty. Your's look beatuiful. xx