Sounds cool... I wish I didn't have so much homework so I could work on my Elvish studies a bit more...
You could check out this site for some samples of poetry:
http://www.elvish.org/gwaith/language.htm
Or you could do "The world is changed. I feel it in the water; I feel it in the earth; I smell it in the air," which is a cool quote. I dunno if you want anything water-related like you said the other one was.
This in elvish (at least according to the movie, and I think they got it right) is:
I amar prestar aen.
Han mathon ne nen.
Han mathon ne chae.
A han noston ned gwilith.
(Courtesy of arwen-undomiel.com)
You could also do some lines from either of Galadriel's songs. I personally like "Like gold fall the leaves in the wind, long years numberless as the wings of trees" and "But if of ships I now should sing, what ship would come for me? What ship would bear me ever back across so wide a sea?" The first is, of course, in FotR in Quenya. The second song can be found in elvish here:
http://www.xs4all.nl/~xelag/quenya_comp_i_sang.html
More elvish stuff here:
http://www.geocities.com/petristikka/elvish/index2.html
EDIT: just realized you'd probably want it in Tengwar; this is a great Tengwar site:
http://www.geocities.com/TimesSquare/4948/tengwar/
Good luck!