Zoe, I'd take up Normhead's point that the less you spend on the body the more you have for lenses. Any of K-30, K-50 or K-5iis would be a big upgrade from your current camera and save you a lot compared with buying a K-3. I see from your profile that you have some good manual lenses but below 80mm you rely on the 18-55 and a 50mm prime. If I were you I'd be looking to fill that gap (ultrawide zoom? better zoom in the wide-normal range? DA 35 f2.4?) before spending all the savings on a K-3. To put it another way, it seems a bit unbalanced to spend the money on a K-3 and then just shoot with the 18-55 kit lens.
Since you often shoot in low light, you would also gain a lot from top-quality noise reduction software, like Topaz or DxO Optics Pro. I have the latter and it's great. What you see on their web site matches my experience.
BTW my mother had Reynaud's (and scleroderma). It's tough in a cold climate.
Last edited by Des; 11-22-2014 at 08:36 PM.