I need certain courses not covered in my undergraduate studies, can I take them at another institution? I recently got accepted into a graduate CS program (provisionally), but I need to take two classes that my undergraduate studies didn't cover. Now, where I got accepted those courses aren't offered until the fall which poses a problem for me. I would only be able to take one of the graduate courses without those missing courses in the fall.
Question:

Could I take those classes at another institution I'm not enrolled in?
If so, is there a database I could search comparable CS classes?

I know the standard procedure would be to contact the graduate school's admissions director and see what they recommend, however I feel like I've already annoyed them when I had to defer my summer acceptance. So, I would like them to have all the information needed in order to make that discourse easier for us both.
I would still suggest you contact the admission director (one more time)! He is the one with the "right" and "only" answer you need to follow. All what we can do is share relevant experiences that may or may not be along the lines of your school's standard/system.  

Having said that, If I'm not mistaken, I think you can take the courses in other schools (as long as they are accredited and/or sister schools + cover a similar syllabus as the one your school has). As for a database, try to look through your school's graduate handbook or admission website.