Based on this numbers I do recommend that you give ROracle a try (even though the numbers came from different machines). If you have trouble installing it post a question here. We'll be more than happy to help. Take a look at the INSTALL file. This should get you started. One thing that is not mentioned there yet is a problem setting up Instant Client SDK from a .zip file. Once unzipped it will not have libclntsh.so symbolic link. You will have to create it manually.
R> con<-dbConnect(Oracle(), "rquser", "rquser") R> system.time(dat<-dbGetQuery(con, "select * from ontime_s")) user system elapsed 5.740 0.144 7.501 R> dim(dat)  219932 26