There is no way to increase the space as it is a physical chip. But take heed of Optimistprimes posts as it could be something else.

Won't really know until you check how much rootfs space you have
(In terminal run df -h (You do not need to be root))

If you have very little space then it is a rootfs problem. if you do not then you need to do a spring clean, search the forums and see what else can be found, as you are not the only person with these problems i feel.