Hello, I paid for a full year of my forum to be ad free, for my members and I Chose a month free for guests. I would like to make it a full year for guests as well now. However the options are either just for members and members and guests. Do I just continue and pay the members and guest price and will it subtract that price since I already have it a year fee for logged in users.

Also, I added storage to my forum, however it says it is about to expire? What... it expires? I thought I needed to get more when it was used up? Am i reading this wrong?

When the time is up, you will not be able to upload any more images if you still have space left.  The images you have already uploaded will still be there.  If you want more storage space, you have to paid for the space you have already used and for extra space you want.

For the ads, after a month, guests will see ads.  Members will not since you have a year for members.  To have it for a year for guests, you will have to purchase it.  I would just wait for the year one to expire and purchase the year one for members and guests.

For your storage if it says its about to run out this means you have only asked for this for one month or what ever.

My advice is always do all of it for one year as it's cheaper and you don't have to worry about it for one year.