Hi

I am afraid you are right, and this level of theory is not included in Gaussian 03. The solution for the basis set is very easy. You can define it manually using the gen keyword and the basis set exchange database (https://bse.pnl.gov/bse/portal). Just look for your basis set and the atoms you need and copy the numbers (notice that you must select the format as gaussian 94).

Unfortunately, most of the Minnesota functionals are not included in Gaussian 03, and this is more difficult to solve. Gaussian 03 allows to define some custom DFT functionals, but it can be quite complicated. I think the best option (unless you are very confident working with these user-defined parameters and IOps) is to upgrade to Gaussian 09 or if that is not possible for you, just choose another functional included in G03 (http://www.lct.jussieu.fr/manuels/Gaussian03/g_ur/k_dft.htm).

Good luck,

Martí