Reverse osmosis or fluoride free plastic bottled water?

I live in a country where the tap water is very bad. If one would drink it you will most probably have diareah an hour later. I think it has much chlorine and fluoride in it, so everybody buys water at the store here.
Now i have only two options:

1. Buy a reverse osmosis filter, but i dont know if that is enough to make this water healthy.
2. Buy big plastic 5 liter bottle springwater that are fluoride free. Glass or carton waterbottles don't exist here.

I always drink plastic bottled water but now i'm reading lots of bad stuff about it. Would it be better to buy a reverse osmosis? thank you

Maup - The type of plastic will determine the possibility of BPA (bisphenol-a).

I'm not sure how it is done in Europe, but this site here shows how to tell on the bottom of the plastic bottles, the risk of BPA exposure.

http://bsalert.com/artsearch.php?fn=2&dt=1&as=2319

Keep in mind that heat is required to release them. So if you're using the #7 which found in many large bottle containers at the office, it may not be so bad unless the water is heated and then released into the container.

Regarding reverse osmosis, it might depend on the cost.

Thanks for that link CS. On the bottom of my bottle it says 06 without a recycle triangle and PET.
So PET means: polyethylene terephthalate and if i understand it right its ok for 1 time use.
But what does 06 mean?
On the link 6 means polystyrene and that is bad so i hope they mean something else

Am i better off buying reverse osmosis? They are pretty cheap here but do they completely remove all the fluoride, chlorine and the rest off the bad stuff?