Bug identification, please!

[aleksandra7]

I've noticed this bug in my home. I've never seen it before or had any problems with it, but from summer till now its bugging me because when it bites, it creates me terrible reaction, area of 3 centimeters around the bite (which radius is 2-3 milimeters and white) becomes red and the itch is awful.
The bug itself is about 3-5 milimeters long, really small and I don't have idea where it comes from.
Last three days I've been noticing them, so I killed them (it isn't a crime after what they did to me) and took photos.
http://img146.imageshack.us/img146/5725/buba1j.jpg
http://img831.imageshack.us/img831/3243/buba2.jpg
Can you tell me what is this bug, how to solve the biting issue and get rid of them for good?
I'm from Croatia, and live near the sea, if that makes any difference.
Thank you!