Your pump head may have a grommet inside that can be flipped to interface with the Presta valve. If it doesn't, you can either buy a new pump or buy the adapter that was mentioned above for about $1.50 at most bike shops.

Also, I am interested in the choice of sizing of the bike. The shop I work at sells Giant, and I would have told you that that bike is too big for you. Compact frame geometries are supposed to have a lot of seatpost showing, and I am not seeing that in your picture.