Which direction should PSU fan look at ?

Hello xantier;

The fan should face toward a direction where it can pull in some air.

You could flip the PSU case to have the fan face into the case or down to face the air filter/air intake source.

What case do you have? Where is it mounted?

http://www.aerocool.com.tw/index.php/products/chassis/3...
it is mounted at bottom and fan looks downside

by the way speedfan shows +12V as 11,35V but bios shows 12,04V which one is true and is it normal ?

It's normal to have different voltages reported.
Neither one might be right. But BIOS is usually more accurate.

Your fan is drawing air into the PSU and exhausting it out the rear.
As long as your case doesn't sit on carpet and it doesn't collect too much dust on the filter you'll be OK with that setup. Check the filter pretty often, at least once a month, till get you a feel how often you need to check.