I have morrowind and the two expansion packs installed on my computer but they are old and not GOTY edition. When I point to the install directory with the new morroblivion installer does it need to be GOTY edition? Do I have to buy the whole game all over again?
I got it. Thank you!
I got it. Thank you!

No, it does not actually have
No, it does not actually have to be GOTY. You just have to have Morrowind + both expansions installed, and point the installer to your Morrowind Directory.
Then point the installer to your Oblivion directory, and it will extract a .rar file in the /data/ subfolder. Then extract the morrowind_ob.esm file from that data file.