Yes you can, although it'll be a bit more difficult. Here's an article that tells you how to do layer masks in photoshop: http://graphicssoft.about.com/od/pse...layermasks.htm.

You need to duplicate the layer with your image (in colour) in it. You turn the second layer into black and white by using whatever method or plugin you like. Then use the layer masking technique shown above to create a mask for the black and white layer. Then use the brush tool to paint white (to keep black and white) or black (to show colour). I suggest using tha paint bucket to paint the mask white (turn it completely black and white) and then using the brush tool on the small pieces you want to make color. Hope that helps!