1. If you're having a hard time with the language of the sites you can download
Google Translator for Firefox for example. If you use another browser you have to search for another addon, since I just use Firefox.
All three sites you mentioned above have an index of all their games. On foolmaker you have to click on the fourth tab on the left side, on gamekn you have to click on the second tab on the top and on seiya-saiga it's the third tab on the top. Then you just have to search for your game (with the japanese title of course).
2. If you're using Google:
For a walkthrough: "チュートリアル" + "game title" OR "ゲーム攻略" + "game title"
For a savegame: "セーブデータ" + "game title"
In each case without the quotation marks and without the plus :)
3. Regarding your game:
Here is a savegame to unlock all CG's and
here is a walkthrough.
Yeah, I found both of them with Google too :D
4. If you're just looking for a savegame I would recommend you sagaoz.net (the one link from above). If you can't find the savegame on foolmaker you'll most likely find it here.
5. Since you're right that this thread was inactive for a long time now I would also recommend you the
Visual Novel Cafe here on AS. There you'll have more luck than here if you have some problems :)
Edit: Yeah, I found out that the link to the walkthrough doesn't work how I would like it to work. In any case, open the link, click the fifth tab on the left side, then click the third tab on the top (after NEW) and then just search for "兄嫁・恥辱のタイムセール".