There is no way to increase the memory for the G33/G31 integrated video, beyond maxing out the system memory that your motherboard can use. Your video chipset uses shared memory with the main memory used by the system. Short of going into your BIOS and allocating (if your BIOS supports) a higher amount, you are out of luck.
Your best option to overcome this issue is to get a compatible, stand alone, video card and not use the integrated video at all.
What make/model of HP are you using?