Hello again,
Are you trying to change the repository with yast ( the nice graphical interface ) or zypper ( the easy, but potentially confusing linux command line program )?
Could you be more specific than “but it did not work for me”? Did you receive an error message? If so, what did it say? … etc.
If you are comfortable with linux command line programs, use zypper, as it is easy to copy and paste exactly what you are doing into a forum message.
If you are not … don’t sweat it … the Yast repo management tool is very solid … just requires some extra English to describe EXACTLY what you are doing for the purpose of telling us …
Whether you are using yast or zypper, it is not more complicated than feeding the app a url, such as “http://77.88.19.68/opensuse/distribution/11.3/repo/oss/” which I just randomly choose from the list of repo mirrors here: openSUSE Download Mirrors - 11.3. Try to add the same url: “http://77.88.19.68/opensuse/distribution/11.3/repo/oss/”, assuming Russia is not too far to travel … 
But let me back up just a little bit … the mirror list contains bunches of links, organized by geographical region. For now, just look at those labelled http. If you click on any of these, your browser will take you to that url. That may or may not be the actual url for the repo you want to add. In the example I gave above, I clicked “http” on the fourth item in the list “Asia” with a Russina flag next to it. It took me to “http://77.88.19.68/opensuse/” … from there I clicked on “distribution”, then “11.3”, then “repo”, then “oss”. So I arrive at the url I stated a few sentances back “http://77.88.19.68/opensuse/distribution/11.3/repo/oss/”.
I know this is a valid url to give yast or zypper only because I am familiar with the directory layout of SuSE repositories … I see the directories “boot” and “docu” and files like directory.yast. I’ve simply seen the directory layout enough times to recognize that I’ve clicked my way a valid repo directory.
Sorry if this was more detail than you actually needed … I’m not sure exactly what you are missing based on your post … so excuse me if I erred on the side of overkill.
When a repo is successfully added, both yast and zypper will display a little info while adding it … ask you if you want to trust the key, etc. If adding the repo fails … they will give an error, hopefully telling you why it failed.
Good luck!
cwight