Dell Inspiron 660 Mini Tower Video Card Slots

Hello all,

Im looking to upgrade the video card in my Inspiron 660 Mini tower (not the slim) and have been going back and forth on a couple of things. I know the power supply is 300w and to upgrade to a lot of the newer cards would take a replacement of the power supply. That's one option. The other option that Im leaning towards is keeping the 300w power supply and buying an HD 7750 of some sort, which if I understand correctly, does not need the power cable from the power supply and will run on the stock power of the motherboard (or something to that effect).

The cards they recommend for a quick upgrade for this unit is the GT 640 or the HD 7570, but I read elsewhere on this site that if the GT 640 can run on that power supply then the HD 7750 will run on it also. That's why im leaning that way. I do game a bit, but Im coming from an oooooold P4 with an AGP card, so any of these are a huge upgrade for me lol. Also the monitor Im current using is only 1440x900.

Most of that I understand, but the one thing I cant find any info on is whether the Inspiron 660 Mini-Tower can accommodate the dual slot cards. I see the HD 7750 in both dual slot and single slot forms, but I haven't been able to find any info as to whether this model Inspiron will allow me to use a dual slot card. Thanks for any light you might be able to shed on this for me.

Current Setup:
Intel i5 3330 @ 3.00 Ghz (quad core)
8 GB RAM
1 TB HD
DVD Burner of some sort
300w PS