LAT/LON to UTM in R

Hi,
I am trying to convert lat/lon to UTM but my results are extremely flawed.
Is it because of wrong UTM zone or my lon points are negative?

I read a shapefile from ESRI using:
library(rgdal)
stations <- readOGR(".","stations")
print(proj4string(stations))
## +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs
 How to convert to UTM the following lat/lon points? Reproducible example
at the end.


library(sp)

coordinates(xy) <- c("X", "Y")
proj4string(xy) <- CRS("+proj=longlat +ellps=WGS84 +datum=WGS84
+no_defs")  ## for example
res <- spTransform(xy, CRS("+proj=longlat +ellps=WGS84 +datum=WGS84
+no_defs"))
res
as(res, "SpatialPoints")
x<-as(res, "SpatialPoints")
xx<-as.data.frame(x)

#OR

project(as.matrix(xy[,c("X","Y")]), "+proj=longlat +ellps=WGS84
+datum=WGS84 +no_defs")
Everything goes wrong with the values.

Please help.





Zilefac.