Nice!
Actually I'd used 18F2550 that has same architecture (EEPROM, PROM and RAM ) except pins count as 18F4550 for my GLCD cluster.
So you can easily transform your code to drive GLCD to display whatever data is available.
For driving GLCD, the important thing is compiler selection. Many are available for download from internet. CCS and mikroC for PIC are example. I'm using later one for my GLCD projects.
It has built-in libraries to drive GLCD (128 x 64) and sample codes along with reference schematic in software help.
You can use these for starting projects.
For downloading free version, here is link http://www.mikroe.com/.
After getting some hands on how GLCD is interfaced with pic microcontroller, you can built your own codes to display data in different fonts for nicely look. For further reading how to write code for GLCD, have a look in help on GLCD library.
If you're in LAHORE, you can get GLCD easily from Hall road in price of 1500 or you can also order online http://www.evselectro.com/
As you are already using pic so I'm sure you will have programmer for pic as well.