Bestbuy are regarded as being full of s***, i know this and i dont even live within 10000km of one...
For software, i would recommend sony vegas or adobe after effects (both are pay versions, but theres always torrents XD), or you can use old trusty windows movie maker, but is prone to crashing a lot, and only renders at 480p, which is below what you want...
As a side note, i can do video editing fine on my 2.0ghz dual, 2gb ram, and intel gma950, sure i have to wait a few more seconds for it to be finished, but so what...