string to hex value

[fallen]

So in my program I ended up with a hexadecimal string.
eg: ad='0xc034dda2' and i need to convert this to a hexadecimal value because i need to perform arithmetic operations on it (subtraction and addition)


I've tried searching forums and such for solutions, but nothing so far helped.
How exactly do I go about that? int() obviously won't work, as hex () won't either... so I am at a bit of a loss...

Thanks