for terminology this may help, look at the section "Conventional Threadless Headsets"http://www.parktool.com/blog/repair-hel ... threadless
from the top...
- top cap, the bolt in the middle is only there to lightly preload the bearings before the stem is tightened, it does *not* secure anything
- usually at least one short spacer 3-5mm, but may be bigger or multiple spacers
- the stem, the stem clamp is what keeps the bars firmly attached to the steerer tube that runs down to the forks
- then zero or more spacers
- then the top of the headset
- then the frame
if the bars are too low, you have two options that don't involve new bits...
if there's one or more tall spacers above the stem, then one or more can be moved below the stem***, which will raise the bars - but usually you need at least one thin spacer between stem and top cap (to make things fit, you can buy spacers of various sizes)
***it's important that the correct amount of steerer tube is clamped by the stem, this is safety critical
, if you do not know how it should be done, get someone to show you, or read up, or get the bike shop to do it
if the current stem angles down, it can be taken off, flipped 'upside down", and refitted, this too will raise the bars, how much depends on how angled the stem is
get a new stem with a steeper angle to give extra height
the nuclear option is replacing the forks, with the steerer not cut so low and with extra spacers - a new stem will be a *lot* cheaper