I have never in my life said [babizan the foun], but I'm only 66 so I still have time to reform my pronuciation. Seriously, I wouldn't spend a dime on either of those courses.
It will be rather difficult to sound like an American as long as you are living in the UK. The best way to acquire any accent is immersion in that accent, and obviously you are immersed in BrE. But if you want to learn AmE pronunciation, watch and record CNN. Then try to duplicate the pronunciation and record yourself. Compare the two recordings. The more you immerse yourself in the sound of AmE the more your pronunciation will tend in that direction.