Yes you can upgrade your Hosting Package for example if you are on the 200MB 60,000/= per year package and you want, you can upgrade it to 500MB 90,000/= per year Package by paying 30,000/= then you will be billed 90,000/= per year.
This can also be calculated on a monthly basis ie how many months left for your current Hosting plan to expire then we calculate that for the new Hosting plan price.