Welcome to INTERCOT Stacey!
I am not 100% certain, but I don't believe you are able to do it through Tavelocity.
I think you have to go directly through WDW or through a travel agent to get a package with dining.
The Disney packages with dining do not discount the room rate. Travelocity gives you a break on the room, so I don't believe they can give you a package.
Since you have already scored a good deal on your room, it won't be so bad to just pay for your food without the plan.