It created a PhotoStream folder so look for that in Your Documents> Picture Library and it should be there. The best way I have found and the fastest is to download
iCloud Control Panel 3.1 for Windows and it will install it's own folder in the Picture Library called PhotoStream. Only choose photos when you wish to sync and only choose Photos to sync when you log in using your Apple ID. Be on wifi which is key. Open and then close your phot app which triggers the sync and by the time you are finished thanking us here...LOL your photos will now be on your computer in that folder and YES they will stay on your phone until you remove them if you choose to. Good luck. I have been doing it this way and it works great in less than 5 mins. Don't forget once you are done to log out of the control panel.