Need help how much ram can I use

[#1]

I have a Winfast K7NCR18 D pro m/b http://www.leadtek.com/eng/mainboard/overview.asp?lineid=3&pronameid=74
At present is has 1Gb of ram installed as 2x512mb. I have a spare ram slot and I'm using speedboost, when it works. I wish to upgrade my ram to 2 Gb, can I just purchase a 1Gb chip and place that in ram slot 3 or will it cause the machine to blow up and go mad with errors.
a one gb ddr3200 chip is about £30 and I can't strecth to the £70 plus for another matched pair.
Cheers
A

[#2]

You should be able to buy the 1 gig but to be sure read your MB manual as you may have to move the 512's to another slot depending if its using duel channel's.
Most manuals give you a list of were to put the ram and the combinations you can use. If you go to a good retailer and tell them the board etc and ask if you can return it if it doesnt work.
If you get a gig and it wont work with to 2*512 you could just put the gig in so you are no worse off. Then sell the 2*512 and with the money get another 1 gig stick.
At the worse it wont work but adding a gig wont blow it up or do any damage providing you put it in the right way

[#3]

manuel says:
supports dual channel access use 1 + 3 or 2 +3 to get better performance.
Does the dual bit just improve the performace of the two same sized module working together. Will the seperate non matched module slow the other two down.
Q & A states
Q:
How can I get maximum performance out of WinFastK7nCR18D/G (Pro)?
A:

The WinFast K7nCR18D/G (Pro) series motherboards can support Dual-Bank function, so if you use memory boards in DIMM1+DIMM3 or DIMM2+DIMM3, the system performance is maximized.
The manual has no table of installation module configuration
A

[#4]

so if you get a 1 gig it will have to go in 2 if the 512 is in 1 + 3 or put it into 1 if they are in  2 +3.
That way the 512 will use duel and the 1 gig will be on its own