Want to upgrade my laptops hard disk and RAM

Hello everyone,

I own an Acer Aspire 5114, powered by AMD Turionx2 1.8Ghz, has 2gb of DDR2 RAM, 512mb ATi X1600 and 120gb HDD. I would like to upgrade my laptops hard disk. I searched quite a bit but I'm not sure if its possible to upgrade. I do not know of the specification and configuration required. I'm particularly looking at a 320gb model from Western Digital, as 500gb is not available. Even if it is available, will it be compatible with my laptop?

I would also like to upgrade my RAM too, to 3GB. I came to know that the RAM is upgradable by visiting Crucial's website and running the Memory Scanning tool. Is there a similar way to find out whether upgrading the hard disk is possible?

I went out to check for a monitor too, because I find that working in 3dsmax in my laptop is too tight, and so I need more screen real estate. I prefer 18.5' onwards. Samsung, Dell and Acer is available. Which one should I buy and why? Will widescreen work properly with my laptop?

Please advice.

Cheers,
Milad