SIMPLE Price converter

VERY SIMPLE. I have a file with one price column (column 5). I need the prices in these columns multiplied by 1000 and the result given to one decimal place. Example Current = 1.1125 Result = 11125.0 or Current = 1.11255 Result = 11125.5 There are alot of files so the code must be FAST. I need to be able to select a directory and the app will run on every file within directory Once complete it saves the results in a new file - same location - with a different file name to identify it. Add the word "Modified" to the new file name. Example file attached