A thorough cleanout internally and replacing the thermal pad between the CPU and heatsink would be a good idea. That should be all that's needed to bring the temperature down.   Upgrading to a 2.5" SATA SSD will boost performance appreciably. Any other upgrade should be considered carefully in light of the value of the system -- complete used systems run in the $30-60 range.  Spending more than that on a system that's as old as this one does not make much economic sense.  
 I am having dell insiprion 14R N4010 model 2011. With 3gb ddr3 ram with 2 slot of 1333mhz speed. Hdd of 250gb.intel core i3 M370[NAME].40ghz. Actualy i want to complete upgrade of my laptop.and most important it is having very very heating effect and due to this heating my baatery is alao gone dead.  So can anybody please suggest what thing should i need to upgrade like Ram,ssd,procesoror anything else. Please any computer techee please help.
Dell inspiron 14R N4010 complete upgrade