I'm not sure this will help, but you may have do this.
First, you should remove the pictures currently in the Camera Roll (Photos), so you won't be duplicating everything. You need to setup a folder, on your PC under "My Pictures", such as "iPad Pictures" and make all of the folders you want, with the pictures you want in them (copy, move or drag and drop, your choice), under that folder. Then go into iTunes, under PHOTOS and select "Sync Photos from" and change "My Pictures" to "Choose Folder" and then choose the folder you created "iPad Pictures" open it and select the folders you want to sync to the iPad. Then sync them.
The numbers you are seeing, IMPRT158 ect., are the numbers that Apple uses to keep track of the photos internally. You should never see these numbers, normally. I am assuming that you still have the pictures on you PC. Use the folder names to keep the pictures by dates. Example: Joey's first bday 12-25-2008, Joey at the beach 7-12-2010, joey at Grandma's 12-24-2010. Hope this helps. Don't know how the got messed up, though.