That barlow is no good. You could of course just throw it in the bin, but I'm sure Striker will take pity on you and give you a couple of bucks for it. Then go out and get yourself a Powermate. It's the greatest thing since sliced bread. The Powermate can also be used to cut shapes out of cookie dough. If you get a big 2-incher, you can make great big choc chip cookies with it.
PS. Ultima magnification will be around 2.2-2.3x with most eyepieces