DPI does not relate to image quality... it relates to "Pixel Density"
I also have a Sony Alpha 350 DSLR, and it shoots at 4596 x 3056 (14million or 14 Megapixel) as stated... printed at 72dpi this would make an image 63inches x 42inches...
Please DONT confuse DPI with sensor resolution!! Most of the time your images would be in the region 12x8 inches or smaller... at 300dpi you would get an image 15x10inches with no loss of quality... and you could enlarge this a LOT before the drop in quality is visible!!
I hope I havent confused things, but DPI is PRINT resolution not anything to do with the cameras Megapixels!!!