Hi reberg,
First of all good luck.
Every situation is different. Your salary of $4,300 per month translates to 15,600 dirhams per month or $56,000 per year. Strictly as a salary that is not a terrible salary and a lot of people live on less. However it depends of your life style and purpose for coming to work in Dubai (to save, because there is no work in your country, for the sunshine, for the additional work experience, to meet different people, etc. etc.)
The bigger problem is the housing allowance. It is outrageous how expensive it is to live in Dubai. If you want to live near the Emirates Towers whee you will be working you probably need 100,000+ for a one bedroom apt. (others in this forum will know best). You may find a less expensive option somewhere else but "less expensive" does not mean half that price! And then you will be living far from emirates towers for example Internation City (which I hear is less expensive, again others on the forum will know). Based on your salary I doubt you will be getting 100,000 for a housing allowance.
I don't mean to scare you with the rental situation but it is a fact that it is very expensive. If you were traveling alone it might be easier because you could share the rent expense with the flat or villa mates. Something that is less of an option if your wife will travel with you. Perhaps the intial sacrify is for just you to come here while you figure out things better (expenses, jobs for her etc). This is particularly so if she is going to give up a job in Poland and come to Dubai without a job.
Also note that you need to drive everwhere. There is no real public transportation system.
I sugges you look at the "Sticky" posts on this forum and on the "accomodation" forum for great advice and answers to a lot of your questions (there are also other threads which you can access by the aid of the "search" feauture - upper right hand corner or by simply reading many of them)
Don't be fooled by the employer telling you that whatever allowance they give you will be "sufficient" because they know that once you land here you will be pretty much stuck.
The "insurance" doesn't sound like insurance to me or it could be very expensive for you. The "bonus" unless in writing and with a specific amount attached to it for a specific result, etc. then it is not a bonus. This is different thant the "gratuity" which is required by law (for every year of service) - it is not an employer "bonus" but compliance with the law.
On the other hand, Dubia is sunny everyday, most people are nice, and it sure is different than Warsaw (but not in a bad way).
In conclusion the salary is livable provided you negotiate a good accomodation package and FIND a place for that amount. Note that rents increase a lot from year to year.
Best of luck.
P.S. someone else just posted this site:
http://www.howdoidubai.com/ as a helpful site for living in dubai check it out.