RIMS Specialized/Alex RHD 29, double wall, for disc brakes

FRONT HUB Specialized Hi Lo disc, 28h, CNC flange and disc mount, polished races, alloy QR

REAR HUB Specialized Hi Lo disc, cassette, 32h, CNC flanges and disc mount, polished races, alloy QR

SPOKES 1.8mm (15g) stainless, alloy nipples

Six bolt disc rotor mount.

The stock wheels are pretty much crap. They are light but not strong. I think I'd prefer strong and not light at this point. The back wheel is the real problem, I haven't actually had much issue with the front. But being a hardtail the back rim is getting beat to hell all the time. I need something better before it is untruable.

I would prefer to go budget a bit since I am probably buying a FS 29'er next year anyway. I plan to keep the hardtail, but only ride it on smoother less technical stuff. So I'm not really looking to drop $500 per wheel or anything.

Can I upgrade for less and still have an upgrade to these wheels? Can I just do one wheel, the back, and leave the front the same or should I be sure to do both at once? Has anyone upgraded this bike and can give suggestions?

I'd prefer a prebuilt wheelset but would consider component parts to have it built. I usually order from pricepoint or jenson, so any links to products on those sites would be bonus.

Thanks a bunch for any help.