You might consider taking it to an Apple store and get it repaired. There's probably no workable DIY that can fix the device at this point. The repair cost could be considerably high, but this will depend on how badly damaged the iPad is.
If no software solution resolves it it may be an actual hardware problem. I hope I don't state the obvious, but you can always try to fix it yourself first. search model name plus "repair guide" on any search enginge.They will show details about about part replacent etc. in detail. There are other websites that sell all the replacement parts, one of the bigger ones is http://portatronics.com (646) 797 2838. Then for the repair itself you can venture to do it yourself, or better ask a friend who has done a similar repair before.