You can do a targeted Update Statistics on single tables, the BoL should help lookup the UPDATE STATISTICS TSQL page.

You can I beleive run an EXEC sp_updateStats in line as well.

however I would also suggest that a Rebuild of indexes be run on a weekly basis during quiet times, 12-5am local is generally a good window.

There are also targeted index rebuild scripts available on line that will hit the worst offenders on a nightly basis (say over 60% fragmentation).

You can rebuild Nonclustered Indexes on the fly but it will impact perfomance a little using something like

ALTER INDEX <index> ON <Table> REBUILD (WITH ONLINE=ON)

(check the syntax in BOL).

I wouldnt recommend doing this with a clustered index though.