PartiotionMagic makes it possible to combine 2 partitions into a new one without losing data.
However thats dangerous stuff. (>50% chance of losing data) especially if youre not a pc-guru. (i even lost a partition once, but i recovered about 99% of its data).
i would suggest deleting one of the partitions and increasing the size of the other. Partition Magic can do that and its way less risky than the other way.