Don't think places like AP/CP accepts installments. I know Courts accept installments but not sure if they do it for 707 or if they even sell 707 in the first place. Maybe you can try places like Harvey Norman or Best.
Personally, I wouldn't go for that route. Most stores which offers installments are the stores which sells strictly according to the RRP, unless they have a sale. On top of that, I believe there is an amount of interest you have to pay. So nope, I wouldn't recommend that but if you're really cash strapped..................up to you.
As for whether if it will last you for 2 years is a question that only you can answer. If you're contented with the images it gives and happy with it, of course it will last you for 2 years, maybe even more. But if you think that you'll need to always get the latest and greatest, then it'll not last for say....6 months. Again, up to you. Good luck.
If you are a holder of a credit card, some stores such as SAFE and Best Denki has installment payments with no interest rate added.
Do look into today's (Saturday) Strait's Times for such establishments and the item you are looking for. SAFE at Alexandra Road Anchorage has the Sony 707. Phone them to confirm before you venture there.
If you are referring to the manual focussing ring, I think it's a fly-by-wire one. In that case, possible cameras that may turn you on are: Fuji 6900z, Fuji S602z, Minolta Dimage 5/7/7i. May want to look into these fine cameras too!