A:AnswerYes, you can. It's a great way to expand storage for photos, music, and documents. SD cards won't be as fast as the SSD, so only put stuff you're not accessing several times a day on the SD otherwise it'll slow you down.
A:AnswerYes, just go to Dell's website. They should have a battery/power-supply section of their website where you can buy a replacement. I wouldn't buy an aftermarket/3rd party/generic power supply as they are not guaranteed to provide the same power level as the OEM one.