I'm inclined to agree with NewToCanada.
That mileage run gets you around 6,400 miles which means you are currently around 28,000 miles and have qualified for *P.
If you are going to fly lots next year, *G would be good to have, in which case you should go for it.
If you are only going to travel a few times, buy the MLL pass for access and enjoy your other *S benefits (I beleive Prestige members get a discount). Even then it might not be worth buying the pass, you might be better off booking on AC.com and purchasing one time passes for lounge access.