Those aren't RAM those are GRAPHICS CARDS, they will not add extra system memory. Also what do you mean running low on RAM ? Do you mean that your system is slow ? Could be that your hard drive doesn't have enough space for the windows pagefile.
However if you were going to add actual RAM
the Acer website says....
Up to 4 GB of DDR2 667/800 MHz SDRAM (single-channel support on two DIMMs)
So you can go up to 4GB on the board, though not sure if you can get hold of DDR2 4GB DIMMs which would mean in theory you could go upto 8GB but there could be issues with the motherboard's bios not supporting that amount of memory.
If you're looking to speed up gaming performance by adding a graphics card I'd go with the Radeon because of the wider memory bus (128bit vs 64 bit on the Nvidia). Both cards should fit in your case as they are low profile cards and I checked the system spec there is a 16x PCIe slot so we're golden there. However if your system memory is lower than amount of memory on the card (2GB) in this case then you'd be creating a bottleneck in which case the 512MB Nvidia is the way forward.
So to sum up if you have the full 4GB worth of DIMMs installed in the memory slots I'd go with the Radeon card, however if you have 2GB or less memory then the GeForce is for you. (Until someone contradicts me)
The graphics card is unrelated to your RAM. The DDR3 on the graphics card will not interface to the DDR2 slots on your motherboard, so you don't need to worry about it.
I believe you may be confused because the graphics card has its own memory. However, when people speak of a computer's RAM, they mean only the RAM installed in the motherboard, not the memory on the graphics card.
Those should be compatible with your motherboard. Before you upgrade ram, you should ask yourself the following:
1) How much RAM do you have already?
2) How much RAM do you need?
2b) How do you know you're running low on memory?
Also, there's no need to bump. It's been only 20 minutes since your previous post. Someone will answer eventually.
If the machine has 1GB of RAM in it and from what I read on Acer's website they recommend single channel memory I'm guess he has a single 1GB DIMM in there. The website indicates 2 memory slots (max capacity 4GB). So I'd say rip out the 1GB module and replace with 2x2GB DDR2 DIMMs (@ 800mhz)....or you could buy another 1GB module and go upto 2GB but I'd have a look inside the case though just to confirm that there is just one memory module in there and not two 512MB modules though I doubt that very much.
I think it would first be a good idea to go onto Google or Youtube and find some guides/video's showing you where RAM is located within a computer, and how to remove and replace the modules.
I'm going to presume your not all that "technically minded" since your not sure what RAM you need or what to do with it and the differences between graphics card memory and system memory. Do some research first and then work out what it is you need to buy