Help needed!

So...I am at a loss of what to do about choosing my first dollfie. I have recently made a deal with my mama that if I get all A's at the end of the school year (June 16th 2011) that she will buy me my very fist dollfie. Originally my first choice was going to be DD Yui Hirasawa, but something about her just doesn't appeal to me anymore. However DD Rin Tohsaka's face struck me right in my heart...I was going to get my Rin from a friend but due to last minute complications it didn't work out. I have heard that Rin Tohsaka is a very~ hard girl to find, HOWEVER I AM NOT giving up on Rin. I was wondering if anybody here new about sites that I can possibly find her at? Or if somebody can help me find the spark in Yui again.