Electronic transformer for LV Halogen lamp in general use

Hi, I am in need of a 9V 1500ma power supply to replace the switchmode psu that came with my el Cheapo Android tablet PC, until a replacement arrives >3 weeks (amidst the Christmas rush as well).

Up to now I have limited my electronics dabblings to 12V 500ma and I have no transformers around that can provide 1500ma current. Well, apart from the Low voltage Halogen Electronic transformer that puts our 12V, 5A (and I think around 40 KHz ac). Please advise me if I can use these for general electronics work.

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The other alternative supplies I have is a Laptop brick that provides 15V 3A and an old ATX PSU that was stripped of a working '486 PC. I also have a car adapter that provides variable voltage from 3-12V. I have on hand L200C, LM7809, LM317 regulators, TIP31A 2n3055 transistors lying around, as well as few of MC34063A.

You're spoilt for choice!
If you can identify the potential divider resistors in the ATX PSU which control the feedback to the regulator chip then you can swap one for a pot/trimmer and crank the output volts from +12 down to +9. Heaps of amps available and no wasted power in an external regulator. A side effect is that the fan runs more quietly!