You can always spend 13 hours with your girlfriend, but to let the opportunity pass on achieving Elite status...priceless! But seriously, if you complete this by next month, you'll end up as you've noted with 4 SSWUs, 2 which expire at the end of February 2010, and a new pair with the 2010/11 Elite kit for next year. That plus MLL access and extra luggage allowance (and the fact there is no instant Prestige) would suggest you'd be a fool to pass up the opportunity. Plus depending upon your other choices, some SWUs or NAUs, and a 50% regular mileage bonus on AC flights (which will apply to the flight you cross the 35K mark for another 3185 to your overall AE balance).
However, just check the AE site to confirm that a Z-fare does accumulate 150% and not just 125%. IIRC some discount ExecFirst fares may not earn the full SMs.