Well, in D&D you don't have to have a GOOD character to be useful or even to participate equally. As long as you haven't hilariously gimped yourself (and it doesn't look to me like you have), you should be good to go.
I played the 4e demo campaign and the most useful stuff I did was stuff any stat arrangement could do. Example: we trip a trap that causes the hallway we came from to start collapsing, and brings two giant statues to life. The statues beat the crap out of us, I get OHKO'd (not dead just ko'd), cleric heals me, everyone's dieing, oh god oh god. One statue dies, FINALLY. Then I ask the GM "...is that door open?" and THROW the other statue into the collapsing hallway. Dex check on a statue? lol.
Then we had to go through the hallway to fight a necromancer. Half of us are hit by rocks. Cleric uses turn undead, which blasts all the zombies into the same damn hallway.
It's clever stuff like that that'll get you through the game, not just stats.