Regarding Visit

Hello,
Sorry for lots of questions related to VISA, but this is best place I have found so far in Qatar to raise question and get correct answers. So please help me with this situation also.
My wife lest Qatar on 28th of February 2010 even though her Visit VISA was valid till 5th of March 2010, now my question is when can I apply for Visit VISA for her again, will I be apply for Visit VISA for her in last week of April and call her back on May 29th or will I have to wait till 5th of June to get her back in Doha.
Hello SambaCool,
Thanks for your answer but I am confused do you mean to say that I cannot apply before 3 months or I can bring her back only after 3 months from exit.
Regards
After 3 months of the exit date from Qatar.