The file's like 3.5 gigs but DVDs are only burnable for 2 gigs per file
Can you guys fix this?

ISO-9660 supports files up to 2 gibibytes or 4 gibibytes depending on the implementation. You can burn the discs in UDF format instead of ISO-9660.
Also, you can just split the file - http://www.hjsplit.org/

Will it still work?

Of course. You just need to recombine it. (It's probably better to burn this tool with the file you're splitting)

I wouldn't bother with splitting the file as every modern burning software should be able to burn a filesystem that supports bigger files, that is ISO-9660 level 3 or UDF. Which burning software are you using? A quick web search will show you how to select the right standard with it.

If you're using the Windows Explorer for burning (Vista and newer) choose the Live File System for burning (it should be the default anyway).
If you're using any version of Nero, switch to UDF.