Hello, Alex,
Whilst some people only use a double-sided wetsuit, in winter the cold wind will blow straight through the older style wetties and refrigerate you. Whilst I prefer a single-sided wetsuit for winter, these are both costly and need a lot of care to prevent damage to the soft, outer material. A maxim is that "Double-sided wetsuits are best for sports IN the water, whilst single-side wetsuits are best for sports OUT of the water".
As a suggestion, you might think about a Ripcurl vest, to be worn under your current wettie and shown here:
http://www.ripcurl.com.au/shop/guys/wetsuits/vests.html. I can’t tell if the current ones use a silver internal lining, like my one has, but they are light, don’t impede your arms (if swimming) and the silver lining reflects body heat, slowing heat loss. Not sure if SHQ or the Zu stock them, but they can always get them. Best bet for a touch and feel would be Mordy Surf Shop and it’s probably worth a call to see what they carry. My one is the 1.5mm thick type and its only drawback is that it sticks to your skin and can be difficult to get off. I lightly dust talcum powder down the arms and shoulders to ease the vest on.
You might look at the NP standard hoods at SHQ
www.npsurf.com/products/protective/hoods-beanies-hats.html and consider open-palm gloves:
www.npsurf.com/products/protective/gloves.html or their equivalents by other makers and at the Zu. The hood's extended neck covers a large nerve area at the back of your neck, which, if it gets cold makes you feel REALLY cold. I’ve tried dishwashing gloves early in my windsurfing career and they didn’t work for me, but as they are cheap, they’re probably worth a go before buying open palm gloves. As a suggestion, one pair of dishwashing gloves on top of another might work.
For boots, I prefer round toe, as the split toe type rode up into the groove between my big toe and its brother, causing severe pain. Designs may have changed since that happened, though. I used zippered boots last year:
www.oceanicaus.com.au/product.php?id=766 and found the zip allowed the boot to come off quickly as I was changing into clothes, a big plus when you are cold. Water penetration through the zip was negligible. You do need to keep your big toe nails clipped really short, as the nail will cut through the boot, from the inside. The Mares NG boot (
www.mares.com/products/divingwear/wetsuits-accessories/?region=as ) looks good, but the Mirage TTZ (
www.capebyronsports.com.au/html/footwear-b008.htm) was a failure for me, as the extended sole coming onto the top of the boot at the front, caught the footstraps causing crashes during gybing (and triple-forward and Superman attempts

). Both boot types should be available from Macs Waterski World in Moorabbin.
There’s over 10 years of trialling the things above and I’ll give it to you for free, but don’t share it with anybody else.
Hope this helps