How to handle large dataframes?

Dear all

I imported a Stata .dta file with the read.dta-function from the 
foreign-package. The dataframe's dimensions are

 > dim(d.apc)
[1] 15806  1300

Importing needs up to 15 min and calculations with these data are rather 
slow  (although I subset the data before starting analyses).

My questions are:
1. Has someone experiences importing Stata files (alternatives to 
read.dta) ?
2. To my knowledge R should not have problems handling dataframes of 
this size. Is there something I can do after importing that makes data 
handling faster?

My hardware is up-to-date (Intel P4, 3 Ghz, 1 GB RAM) and I work on a 
Windows XP platform.
I am working on a Windows XP platform with R version 2.1 (all packages 
updated).

Thanks for your answers.
Christian

Christian Bieli, project assistant
Institute of Social and Preventive Medicine
University of Basel, Switzerland
Steinengraben 49
CH-4051 Basel
Tel.: +41 61 270 22 12
Fax:  +41 61 270 22 25
christian.bieli at unibas.ch
www.unibas.ch/ispmbs