Err... i'd just get the 512 upgrade and stop there. Judging from your graphics and the rest of the specs of the laptop, i'm guessing it isn't for gaming. Correct me if I'm wrong, but you're probably using it for homework/projects, internet, music, movies,programming and maybe some very light gaming (old RTS games etc.) For these purposes, I personally don't believe a faster hard drive is worth the extra $200 in cost. Sure, it'll open up programs and boot up windows a bit faster, but you won't notice an amazing difference when running Office, or IE or C++. If anything, the extra ram will help because the program is loaded into main memory which is much faster anyway. However, if you are doing such activities as encoding or dvd/cd ripping then the extra speed on the HD will def. make a significant difference. The dvd-r/rw drive is a good idea if you want to copy dvd's but a 2.4 drive is pretty slow. will take you a while to burn a single dvd.
In summary, determine what you use your computer for. Personally, I would only get the 512 ram upgrade and save the rest for something really worthwhile (new desktop, new laptop, new car, new shiny thing). Otherwise, if you really do notice the slow speed of the hard drive and/or absolutely need a dvd burner now, then go for it.