If you don't want to take a bachelor of pharmacy straight away, another route is taking a masters of Pharmacy degree after a bachelor degree.
Using University of Sydney as an example, the Master of Pharmacy is a 2 year course with admission requirements of:
1. A bachelor degree
2. A minimum GPA of 5 or a GAMSAT mark of 55 with 50 in each section
3. A certain amount of credit points in particular prerequisite subjects which can be seen at
http://sydney.edu.au/courses/Master-of-PharmacyI'm not too experienced with uni course transfers, but it could be a possibility that you could transfer from a bachelor of Science to a bachelor of Pharmacy.
Obviously though, taking a bachelor of Pharmacy straight from the start will be overall less of a hassle and more straight forward with it only being 4 years in total (as opposed to 5 years with Bachelor of Science and Master of Pharmacy), but particularly because you won't have to fight for positions to enter the Master of Pharmacy (Which will usually be dependent on your GPA or GAMSAT score if you enter through that).
Good luck pursuing your career!
Edit: Just saw this was in the Monash Sub-forum, check this out
https://www.monash.edu/pharm/future/courses/pharmacy/grad-pharmacy