Changing the battery will not be the issue here but accessing it may well be
If this laptop is still under warranty from Dell then they should do this change for you on request.
If it is out of warranty or the time that dell will take is an issue, and you feel up to the task you can do it yourself
Have a look here for instructions .... AhWee.com - How To Disassemble Laptop (Dell XPS M1530) ? How To
Think carefully and good luck