backed up all the files that you may want to move to the Mac.
This includes music, photo's, movies, documents, spreadsheets, etc.
Easiest thing to do is to copy them onto a DVD (or 2) ready for later use.

Your new MacBook has a variety of ports including Firewire 800 and USB.
This makes your choice of external enclosure for the Toshiba hard drive quite easy. Firewire enclosures are a little more expensive than USB ones but both work very well.

The choice has nothing to do with your hard drive but all to do with what enclosure you purchase. I would advise against an enclosure that does not have its own power supply.

You will not need a cable converter but if you go with Firewire you may need to purchase a special cable. Your Macbook has Firewire 800 but you may find that a Firewire enclosure only has Firewire 400. The two plugs are different but, there is such a thing as a Firewire cable that has 400 on one end and 800 on the other.
Alternatively, there is also a Firewire 400 to Firewire 800 adapter.

For a USB enclosure, you will probably find that a suitable cable is included in the price of the enclosure.

Because you backed up all the stuff that you need from the Toshiba drive, you can format it to Mac OS X Extended (Journaled) using Disk Utility once you have connected it to the Macbook.
When you first plug it in, it should appear on the desktop. Mac's can read but cannot write to a disk that is formatted as NTFS so if this is going to be a Mac only drive, reformatting is the way to go.

That should get you started. have all the stuff you need, but you "may" be able to find it cheaper somewhere else.

Good luck