Converting characters to numbers in data frames

I'm sure I'm missing something obvious here, but I can't find the 
solution (including in the FAQ etc.).

I have a vector of names of variables like this: NRes.x.y. where x and y 
are numbers.  I want to extract these numbers as numbers to use 
elsewhere.  I can extract the numbers as a list of characters using 
strsplit(), and convert that to a data frame, e.g.:

NAMES=c("NRes.1.2.", "NRes.1.3.", "NRes.1.4.", "NRes.1.5.", "NRes.1.6.")
NUMBERS=strsplit(gsub("NRes.","", NAMES, perl =T), '.', fixed = TRUE)
NUMBERS.df=t(data.frame(NUMBERS))

But I now want to convert the characters to be numeric.  Using 
as.numeric(NUMBERS.df) converts them, but to a vector.  How can I 
convert and keep as a data frame?  I could use this:

matrix(as.numeric(NUMBERS.df), ncol=dim(NUMBERS.df)[2])

but I seem to be jumping through far too many hoops: there must be an 
easier way.  An suggestions?

Bob

Bob O'Hara
Department of Mathematics and Statistics
P.O. Box 68 (Gustaf H??llstr??min katu 2b)
FIN-00014 University of Helsinki
Finland

Telephone: +358-9-191 51479
Mobile: +358 50 599 0540
Fax:  +358-9-191 51400
WWW:  http://www.RNI.Helsinki.FI/~boh/
Journal of Negative Results - EEB: www.jnr-eeb.org