I thought cinema tools came with fcp?
anyway, what i do is put it through JES deinterlacer,
you can download for free off their website, google it,
Then once youve loaded your file into it, click on the project tab, then select custom on the "convert to.." list, change the settings according to what you want, i.e 720x1280 and 30fps then change the movie speed to 0.500 and voila, that should be slomo.
Not as slow as twixtor, but thats getting boring