How could wget be updated? Automatically or manually?

Manually the up-to-date file could be downloaded from

http://ipkg.nslu2-linux.org/feeds/op...2-2_mipsel.ipk

but this is compressed file wget_1.12-2_mipsel.gz. How could this file be installed? If I extract it with

tar xfvz wget_1.12-2_mipsel.gz

three new files appear: data.tar.gz, control.tar.gz, debian-binary. No ipk.

I need it for the installation of optware-devel which has the problem with downloading the libidn.so.11 library.