Considering you are wishing to do medicine, I'd suggest the following subjects:
-Biology
-Chemistry
-English
(Chem and English are requirements, however I'd strongly reccomended doing Biology.)
and perhaps:
-Psychology? It's a great subject for people interested in the medical fields. It would be a good 3/4 subject to take next year also, as I don't think it really requires 1/2 knowledge.
What subjects and electives are you enjoying this year? It will help you choose the others.
Out of curiosity what ENTER score do you need for medicine i can't find it anywhere, would it be around 97-98
the score is up there with Law. you dont want just anyone to be a doctor handling your life, do you? 
Actually, no it's not. Medicine doesn't solely take the ENTER into account, it also considers interview and UMAT. Individuals with an ENTER of 94 plus great UMAT and interview results have the potential to get in. (Realistically, you need an ENTER score over 93- 95 to be considered.)
Also, Maths Methods (and maths altogether) isn't a requirement for undergraduate medicine at Monash University. (The ONLY u.grad med course lol)
Prerequisites for Monash University: Units 3 and 4-a study score of at least 30 in English (any) and in chemistry.