If you are single and in company accomodation you should be able to save about 4,000 Dhs a month. If you are married with no kids and your wife is working you will save more than that, depending on her taste in shoes and what she earns. If you have kids you won't save anything and will probably have to dig into savings until you get your upgrade, especially if your wife isn't working.
Obviously if you live in a tent and survive on baked beans, or if you eat out everynight the situation changes a bit.
Be warned, Dubai is not a cheap place to live.