I just downloaded bootstrap (~21GB) and started bitcoin base. It shows me that time to sync will be 4 year and 17 weeks? Is it going to change, or do i have to wait that much?
My internet downloading speed is only about 220 kb/s.
The synchronization process has two parts: Downloading the data and verifying it's validity. You already took care of the downloading part by acquiring the boostrap file. Now your Bitcoin Core is building the transaction database by verifying the network's whole transaction history.
The value you are asking about doesn't give you a time estimate, but shows you how much of the data in the blockchain still has to be verified.
You are just at the very beginning, so your client still has to verify the transactions of 4 years and 17 weeks. Since you have downloaded all the data already (it's in the bootstrap file), your downloading speed doesn't matter.
Depending on the speed of your computer, the verification process can take a few hours to a few days.
If you don't want to run a full node and don't want to wait that long, you might want to look into thin clients, such as MultiBit.
By the way, there is a bittorrent download available too, which can give you a head start on the chain.
From Andreas's most excellent book, in chapter 3,
"You can shorten the blockchain initialization time by downloading a partial copy of the blockchain using a bittorrent client from http://sourceforge.net/projects/bitcoin/files/Bitcoin/blockchain/."
About 1/3 of the way down the page.