I took some time away from work and home and ate out (and also tried this year's Schell's Snowstorm - not a porter or stout this time, but a "Dunkel Doppel Weizenbock." A bit lighter than I am used to, but still substantial.) and thus had some time to think without much distraction during the walk to and from the restaurant and while waiting for the food.
In that time I worked out what costs were and how could I could shift things around. When I got home I looked things over again. Decided on a power supply, and then on a case, and checked on memory. And eventually placed an order.
* 950 Watt Corsair power supply. No more power issues with that.
* Gigabyte GA-890-XA-UD3 motherboard. Has about everything and can handle the Phenom II X6 I want to upgrade to eventually.
* Black Mid Tower ATX case - USB, Audio, eSATA jacks on front panel. And no silly windows or effects lighting. Discounted AND free shipping.
* AMD Sempron 2.7 GHz CPU, with cooler. Not much, but still a jump up from the Athlon 2100 (32 bit, 1.7 GHz) I had been using.
* 2 GB of RAM (two 1 GB sticks of DDR3) Free shipping.
* Pair of copper heat sinks for the RAM.
All this for $411.47. That's manageable.
Everything should arrive on or before the 15th. I expect to be reading over things a bit and assembling things with considerable care (that is, slowly) so it might not be up and running right away. But it is soon enough I'm not too concerned about trying to cobble together a Frankenputer while I wait.