Nathalie, unless you are very handy (I'm not!), repairing a damaged bed door panel is a big job. I recommend you order the door(s) complete with new hinges from Forest River. You'll also need the seal kit and a new decal for each door you replace.
FR contact is:
Parts Coordinator – Forest River, Millersburg
Rockwood – Roo / MiniLite / Ultralite
(574) 642-8940 direct number
(574) 343-5947 direct fax
Explain to Sheri what you are trying to do and she'll need your VIN number to ensure you get the right parts.
If you have the old style screw latches, you might want to consider upgrading your latches, too.
You'll want to be certain to stop the leak, so find the source before starting this project otherwise you'll be wasting your time and money putting new doors on.
2010 Rockwood Roo 23SS
2009 Ford F-150 XLT SuperCrew with Max. Towing
2011 Rockwood Signature Ultra Lite 8293SS, 12K Equal-i-zer
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed, 3.73
2010 Rockwood Roo 23SS (2012 - 2014)
2009 Ford F-150 XLT SuperCrew, 5.4L, 4x4, 5'6" bed (2012 - 2016)