How can I remove the dust which came inside my lens ?

Hi all,

A few weeks ago, I noticed that there was some dust on my lens (this
is the original zoom provided with the Nikon D70 camera) so I used a
really bad quality rag (I did not know it was so bad as this time) to
clean the lens.
Unfortunately, some small pieces of rag came inside the lens (and came
between the lenses).

Actually, I do not know how to remove the dust which came inside. I do
not want to disassemble the lens because I am pretty sure I will not
how to reassemble it right. Moreover I am afraid of adding some more
dust doing this.
Now, I have plenty of dark spots all all the pictures I take !

Does anyone have an idea which could help ?

Thanks in advance.