yes you can. however a better option for you is to use an external monitor of your choice. much easier to replace.
usually this means dell will swaps your current mobo with another one that has the gpu of your choice. this should be an upgrade service provided by dell.
other than the above, it's better don't go for it.
bios is a program/firmware resided in mobo that lets operating systems to recognize and make use of hardware it connects to (cpu, ram, intel chipset, hdd, ssd, keyboard, mouse, gpu, etc. essentially every hardware component in your computer)
if your system is stable, you can opt for not doing it. however, it's a simple process. as long as you follow instructions as is, you will be fine.
with that money you can get new mainstream laptops that perform much much better.
I have external monitor, but when I'm traveling i would not want to bring that lol. Anyway just got my Monitor replaced, the light bleed gone almost entirely, just got one small bleed that is barely noticeable i am ok with that.