This topic of external links comes up from time to time so rather than answer it here I just created the article Links Should Not Open In a New Window, that explains why it is a bad idea but also how to do it if you really insist.
I'm not sure I understand what you are asking for in the blog. You can set the page size of the blog list to a small number so it doesn't show old posts. There are archive links by month available in the side bar.
Hope that helps,