Retail and OEM disks are mostly identical - the only difference comes with an OEM_SLP install where the disks have special licenses relating only to that manufacturer's own brand of machine (not your problem here).

Upgrade disks are identical to Retail disks.
You want the SP1 refresh image for your language - the 'master' link we prefer to use in these forums (because MDL is a minefield of piracy and misinformation) is this one here... if you drill down to the Windows 7 page, you can find the language variations that are available.