convert PDF file into words documents

I have 300 pdf files, i want someone to convert those 300 files from PDF format to .docx /.doc (Microsoft word) format. These files should be changed without affecting any changes in layout. I have checked many on line conversion tools, which works great, but they are having few limitations like 2-3 files conversion in a day.. i am in little hurry thus cant wait for many days to get it converted... ITS A VERY VERY EASY PROJECT FOR ONE WHO KNOWS HOW TO DO IT.