Welcome back to the K10D. As Dave says, there's an enthusiastic club here on the forums dedicated to this camera, and with good reason. Used to its strengths, it's one heck of a camera
The DA35 f/2.4 is also an excellent lens, even wide open, and that can be a real advantage when working with the K10D. You want to keep the ISO setting as low as possible - ideally ISO 400 or below - so lenses with wider ("faster") apertures can be very useful. That's a potential issue with variable aperture zooms like the 18-55 kit lens and the Tamron 18-250. Not only do they have narrower ("slower") apertures at longer focal lengths, but most of them need stopping down further still to produce decent image quality. That reduces the amount of light gathered, and forces you to use higher ISO settings, reducing image quality.
For that reason, I suggest you stick with the DA35 f/2.4 and your Tamron 18-250 for now, but when funds allow, perhaps consider another reasonably-fast prime lens - perhaps a DA50 f/1.8, or something longer like the more expensive DA70 f/2.4 or DFA100 f/2.8. All three of these lenses will give you the ability to shoot at focal lengths your Tamron 18-250 already covers, but at wider apertures, so the amount of light gathered is much greater - meaning you can keep your ISO setting lower in a wider variety of situations. Plus, being prime lenses (and decent ones at that), they'll be sharper than the 18-55 kit lens and your Tamron super-zoom