Should I Postpone Graduation to Retake A Class?

[cplantlover2]

Ok, I am in an atypical situation so take a moment before you say "no! it's one class!"

I did my undergrad in computer science and came to the NIH postbac program. I worked in a couple places there but ended up falling into bioinformatics. I've felt for a while though that it may not be my perfect field. After my postbac I got a job doing more bioinformatics and also into a professional masters program I do outside of work. The thing is, the PMS program lets us take some of the courses at the NIH but those don't get counted into my GPA -- so I only have about 5 courses on my transcript! They're As to Bs so if I retake one course I can boost my GPA from a 3.5-3.6 (depending on the outcome of my final class) to a 3.8, which is the highest I have had (undergrad was 3.6). 
 

The other thing is I think I want to continue on to a PhD in something more like organismal biology, although I am warming up to continuing in bioinformatics.

Do I shoot myself in the foot by not retaking one ( or two courses)? If I retake both I could boost myself up to a 4.0!

On the other hand, if it's not that big of a deal or committees would see it didn't take much to change it, is it worth my time to retake those courses?

Edited May 8 by cplantlover2
Mistake in title