I can help on the Gpa front... kinda...
The GPA is used as, well, an average of your overall results. you find the number for your mark, you combine your subjects, and divide them by the amount of subjects. you can do this at the end of every year, semester, whenever...
Total subject mark
HD=7
DI=6
CR=5
PA=4
F=0
eg; this semester;
SubjectA= CR
SubjectB= DI
SubjectC= CR
SubjectD= HD
5+6+5+7=23
23/4 = 5.75, which is a high credit average,
yours, 5.4; medium credit, ie, not too shabby my good sir/madam
GPA is important for things like scholarships; eg, I have to have a GPA of 5 to keep mine going...
and also for things like honours; at csu, you need a minimum of 5 to apply for a position.
I'm guessing the same would be for graduate medicine, the better GPA etc, the better the chance of scoring a position in there...
GPA accumulates over the years, so every single subject you do counts. one fail can demolish a GPA quite well...
hope that helps
REALATIVELY, for you, how good yours is depends on your cohort though, if you are doing a really competitive course [and you want to be competitive], then yours probably isnt that good, but if you are surrounded by "oh I only need to pass" people, then it probably isnt that bad...