The group could also use another primary healer. The more the merrier! The great thing, I think, about 4E group dynamics is that healers can heal in combat while still contributing ti combat. Healing is a minor action (like a swift action in 3.5), and a lot of their combat powers can also dish out healing.
There are a few caster types that can do decent healing as well, but if you just want to dish out lots of damage, one of those strikers would do well. One can't underestimate the advantage of having a good damage-dealer.
--edit--
And if it's a Gish you're looking for, the Hexblade is version of the Warlock that gets a special magical sword/weapon that they channel their magic through.
Sorcerers are also capable of being gish-like, since one of their implements (tools that casters use to focus their magic/attacks) is a dagger, and I believe there are feats to improve the selection of options for that. Also, some builds of sorcerer use strength as a secondary stat, which is perfect for a Gish.
Finally, Bards make more than passable gishes, and their multiclassing versatility can add to that nicely.
