You would need to check with Dell to see if they made your model of laptop with other motherboards and processors.
Usually Dell uses OEM parts in there systems that are not interchangeable.
Replacing a motherboard for a laptop is not an easy job, and you might possibly find so many unexpected problems you have to find ways to solve. Because it is a processor with TDP at only 15W, or in other words, it is designed for low power or quiet laptop. You can never expect such a laptop too much, and it is not designed for professional and/or game computer. So in my own opinion, I would not suggest you to upgrade anything around core components. If necessary, I would suggest purchase another laptop you want.