My 2004 has some rust in that same area, almost everyone one I have ever seen has it in that area and the bottom corner of the rear doors. I have never seen it that severe before. If the rust is that bad it might be cheaper to buy on in better condition than what it will cost to have a body shop fix it.
Audio: JVC KD-ABT22 / JL sub+speakers / Sound deadening
Engine: WR-SRI / RRM 25% UDP / 6G75 TB
Other: RA Mudflaps