I used the similar extract kit where you pick your own fruit flavor. I chose blackberry. Like you I dumped the whole bottle of extract in there at bottling, thinking it couldn't hurt. It has been over six months now and it still takes cheap and fake. I keep offering cases of the stuff to anyone who comes over, just so it doesn't go to waste if someone can palate it, but no takers so far.
On a related note, for your future reference, I recently brewed an all grain hefe and then threw frozen raspberries directly into the keg when I transferred (in a sanitized paint strainer bag). Definitely the way to go. Over the last two weeks I have been able to watch the beer become more and more pink and taste more and more like raspberries. You can then remove the bag of raspberries when you reach the desired flavor and carb back up. Since this beer is for my wife I've been letting it go.
For your current situation though, I would say it depends on how tasty it is. My extract was horrible, but if yours is palatable then you may just want to ride it out. I would be more concerned about blending two different beers than whether it would cut the raspberry.