baglanti means to connect it. This is only charged when you first move into your house and connect it up.
Aylik means monthly fee which is what you would pay every month.
Also be careful as there are 2 price tables. One is limitli which means limited to a certain amount of gigs and the other is limited which allows you to download as much as you can.
If you are on the unlimited package then there will be no upgrade apart from a 18% discount or so as 512 used to cost 99 ytl.