So the 1st time i went into the museum in Shivering Isles i saw ring which i thought would be good for selling so i took it and now i cant remove it because its apparently a quest item and for about 1 min i had the option of selling it to the museum but that option no longer shows up ...

Are you playing on PC?

If not you're probably stuck with it unless there's some exploit for getting rid of quest items I don't know about.

If you are playing on PC, try http://www.tesnexus.com/downloads/file.php?id=10048

so im stuck with it ? ... well i guess i could part with the jewel of rumour that ive had sincem y character was level 1 .... (might actually be better)

Is it the Ring of Dessication? If so speak to Azhajda at Things found. After her quest, do NOT buy it back, or you will be stuck with it forever.

its not an entirly useless ring i dont mind being stuck with it (its actually quit a bit better than the jewel of the rumar since unlike mrrowind walk on water doesnt make teh water solid so i can still jump through it and swim)

Not entirely sure, but it's always possible you might want to swim through a section of flooded dungeon, and not be able. Personally, I would stick to the Jewel of Rumare, even +4 athletics is a slight boost to swimming speed.