The iPad includes a one year warranty, or if you are within the return window for payment credit, you can return it for payment credit. You must return the iPad and all package contents to the store where it was purchased.
The quickest way (and really the only way) to charge your iPad is with the included 10W USB Power Adapter. iPad will also charge, although more slowly, when attached to a computer with a high-power USB port (many recent Mac computers) or with an iPhone Power Adapter (5W). When attached to a computer via a standard USB port (most PCs or older Mac computers) iPad will charge very slowly (but iPad indicates not charging). Make sure your computer is on while charging iPad via USB. If iPad is connected to a computer that’s turned off or is in sleep or standby mode, the iPad battery will continue to drain.
Apple recommends that once a month you let the iPad fully discharge & then recharge to 100%.
How to Calibrate Your Mac, iPhone, or iPad Battery
At this link http://www.tomshardware.com/reviews/galaxy-tab-android-tablet,3014-11.html , tests show that the iPad 2 battery (25 watt-hours) will charge to 90% in 3 hours 1 minute. It will charge to 100% in 4 hours 2 minutes. The new iPad has a larger capacity battery (42 watt-hours), so using the 10W charger will obviously take longer. If you are using your iPad while charging, it will take even longer. It's best to turn your new iPad OFF and charge over night. Also look at The iPad's charging challenge explained http://www.macworld.com/article/1150356/ipadcharging.html
Also, if you have a 3rd generation iPad, look at
Apple: iPad Battery Nothing to Get Charged Up About
Apple Explains New iPad's Continued Charging Beyond 100% Battery Level
New iPad Takes Much Longer to Charge Than iPad 2
Apple Batteries - iPad http://www.apple.com/batteries/ipad.html
Extend iPad Battery Life (Look at pjl123 comment)
New iPad Slow to Recharge, Barely Charges During Use
Tips About Charging for New iPad 3
Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips
In rare instances when using the Camera Connection Kit, you may notice that iPad does not charge after using the Camera Connection Kit. Disconnecting and reconnecting the iPad from the charger will resolve this issue.
There are numerous posts on battery life fixes, and unfortunately it's a hit or miss. I had to totally drain mine a few times and fully recharge to get to close to the 10 hours average mark. Now my wife has stolen it from me for the time being untill I get her one for her birthday. 3-4 hours is a very low amount of time even if you're running with everything on. So, I would think to discharge a couple of times and recharge to 100% and if that doesn't work think about exchanging it. My previous new iPad was a little finicky so I did exchanged it after several trouble shooting scenarios. Now it charges overnight and lasts around 10 hours so I'm happy with it now (Would be just as happy with 6-8 as long as it gets through a day).
On a side note some of the apps do tend to be a bit more graphically intense and seems to drain the iPad faster, but if you actually check to see how much time you're using it total you should see between 8-10 on average.
Dah-veed ....... nice one, followed your advice and it has cured the problem straight away. My ipad had got to point where it was losing approx 80% of its charge during the day without being used at all and then a full overnight charge, using the wall socket with the ipad switched off, was only adding about 50% battrey power back in after a good 7 hours of charge. It now charges back to 100% and is still reading 100% a full day after last charge. Hooray !!