Scrape a vBulletin Forum

There is a forum with many important data for me.
The server got unstable these days and there are no new posts so I want to scrape them.
Site is in Vietnamese, runs vBulletin 4.2.5.
There are no capchas.
I tried wget -r and things but it's too slow.
Please help
Thanks

Url: http://mobileviet.info

Sitemap:
{id:"sitemap code"}