There's a seperate thread on here on winter tyres but the recommendation is a set of steelies in 14 inch with Contis. IMHO you would be better off buying them now before prices start to rise and save the alloys when your 'summer' comes back in. Good to see that you have the option of heated seats. IIRC it was only available on the US models.
If you decide to go for the A500 at a later stage you should get a good trade in value on your TA. 1.4 suffers more depreciation compared to a 1.2 but makes them a good secondhand buy.
Best of luck with the order for the TA !
I should just mention that they use different winter tyres in the Nordic countries to cope with the lower temps so the good brands might vary a bit. Nokian's are always worth a go as the finns know what they're doing when it comes to winter tyres. In Helsinki last year I would say that almost 80-90% of the cars probably used Nokian's, Conti's or Michelin's.