Is your internet through a DSL or Modem?
If the first and it's wireless, Make sure to check that no one else on the outside is using your bandwidth. Secondly, Find out what the other users of the DSL in your household are using the internet for (Youtube, iTunes, Gambling etc) as that could slow you down. Thirdly, Your ISP could be the problem as i've heard that a few ISP's around Eastern Europe have a lot of management difficulties and are attempting constantly delayed maintenance, Something about upgrading their systems or something. Could also be bad weather conflicting with your telephone pole or the outside telephone cable leading to your property could be damaged if three of the main colour coded wires inside are damaged. Finally, If you have a home phone and a DSL (router) test the phone to see if it knocks your internet out while it's in usage. If that's the case, You need to get a micro filter installed so both can be used at the same time without interference.
If you're using a modem, What kind of deal are you provided by your ISP? Most modem package's have a set monthly allowance on MB usage and once the cap has been reached, It'll be slow for the remainder of the month. It could also be that they have relocated their broadcast transmitter causing the speeds to go slower over the distance.