Pretty n00b Mushkin DDR2 Ram Q?

[SILVR 6]

I"m looking to build a SFF computer using Asus' N4L -VM Core Duo Mobo. I"ve looking at getting Mushkin Xp PC2-5300 3-3-3--10 ram. My question is becasue money is a bit tight, is it alright to buy the 1X1gb stick of ram and then later on add another stick of the same ram, or is that pushing my luck in terms compatibilty. Would I be better of waiting a bit and grabbing the 2X1gb kit. Thanks

PS I know about the aopen board for core duo's but I won't be doing any overclocking. Just want ram with tight timings.