"R console memory limits"

In using the R console, I get the following error  'Error: cannot allocate vector of size 412.8 Mb'.

Running memory.limit() gives 2048, and I am unable to increase it.

I am using 64 bit Windows, with R-64, and this limit is not there when I run R separately.

Is there some setting with the R addon that I should look into?

Thanks for any help.
-sb