Wifi assistance - please help

I live in an area that has free wifi. My problem is that I get a strong signal outside of my room (outdoors) and almost nothing inside. I'm pretty sure it's because of the metal walls. I live in an apartment block made of renovated cargo containers.

Is there some sort of antenna or repeater I can mount outside, I checked and I'm allowed to do this that can boost my signal inside? Like a small roof mounted antenna and a repeater inside? I suppose an external wifi dongle and a long USB cord would work, but I would prefer to be able to use all of my devices (phone, tablet, laptop).

If anyone knows of something that can help I would greatly appreciate the advice.

Ahrimon

Wireless access points generally come with external antennas. All you should need is an outdoor rated antenna (and mount) and cable to run it inside to the WAP itself.

They also make wifi "range extenders" with removable antennas. Grab a mag mount wifi antenna to mount outside a window. They usually give you about 6 feet of wire. I use this setup in several warehouse like buildings and restaurants. Whole setup might cost $70 for quality stuff. Check Amazon.

Thanks Greyhawk009 and Man in the Funny Hat.