RAM question for Inspiron 9300

Hi, I've been using my Inspiron 9300 for almost 3 years now, and it desperately needs a RAM upgrade. I currently have "512MB DIMM_A in Memory Slot 1" (according to Dell's online system information tool) and "2 H5514 DUAL IN-LINE MEMORY MODULE..., 256, 533, 32X64, 8K, 200, 512" (according to original specification page using service tag). I have a few questions about that;
1- What speed memory do I have, and what are they compatible with?
2- Do I need to upgrade using pairs? If I want to go for 1GB, do I have to buy another 512MB module, or can I use just one 1GB module alone?
3- If I don't have to use a pair, can I use my existing 512MB with an additional 1GB module?
4- whats the best place to buy these in UK? Dell or some other website?
Any and all replies will be much appreciated.

 

Try the cruical memory configurator, at www.crucial.com it will tell you exactly what you have and your options to upgrade.

 

you just need any ddr2 so-dimm ram.

 

With this information: H5514 DUAL IN-LINE MEMORY MODULE..., 256, 533, 32X64, 8K, 200, 512"

Its telling you that you have 533mhz, you can buy a single 1 GB 533mhz, you can also buy 2 of those, they will have to be the same speed, or you can add 512mb to the other dim, it has to be 533mhz.

 

I have a 667Mhz stick and a 533Mhz stick in my Inspiron 9300. They do not have to be the same speed. Just atleast 533Mhz