Decimalising RA and Dec Values

Hi guys. I'm stuck on a really annoying problem at the moment.
Basically, I've been tracking the positions of a number of asteroids
over the last 2 months and using a program to output the RA and Dec of
the asteroid relative to it's position to the other stars in the sky.
Now so far I've been inputting the RA and Dec's in the following format
into an Excel spreadsheet:

00 03 34.43

Now I'm in a bit of predicament because I need to start playing about
with this data, so I need it in decimal form (i.e. 0.00054°) (note
these are completely random values I've giving ). However, because
I've been using spaces to separate the degrees, arc minutes and arc
seconds, Excel will not read the values as actual numbers and just the
cells as a zero.

Does anyone know of anyway that I could somehow get Excel to insert
colons into the two spaces, or get it to recognise numbers written in
this format?

Kind Regards,

Matt