GUIs and combining files

I'm still relatively new to C, so I'm no expert. However, I'd like to use some complied C programs in conjunction with programs I've made in higher level languages.

For example, I've made a C program. I want to give it a GUI I've made in another language (don't know which one yet, open to suggestions). How would I do this (which would require them to share variables, I'm assuming)?

Does C have something similar to AutoIt's FileInstall function that will let me embed an exe into my C program for later extraction?

You could create a DLL in C and create your app w/ GUI in another language, then call the DLL functions from the GUI code.
How this can be done depends on what language you want to use other than C.

Thank you!