Sarah, this might be a better link:

http://www.dele.org/?page=dele/intermediate-mid-threshold-level

That specific link is for a B1 test, but there are others on the sidebar.  But what makes this link interesting is that there is a link at the bottom for the answer key.  Tests without answers can be worse than not tests at all.

A friend of mine decide to buy a book for his DELE preparation. 

http://www.amazon.com/Preparacion-DELE-Libro-2014-Spanish/dp/8490816751/ref=sr_1_1?ie=UTF8&qid=1424364502&sr=8-1&keywords=dele

I found these:

http://diplomas.cervantes.es/en/information/sample_examination_papers_audios.html

Thanks for your reply, Camilo! The problem is just that I don't have access to such books here in Nigeria. We don't have Amazon and Spanish isn't really common here. That's why I have to stick to the net.

You sir, deserve my upvote! Thanks Dave :)