You might check with the local smoke shops, where I live I have no B&M close, but there is a smoke shop that carries a very limited and overpriced selection of e-juice. Worst case, go to wal greens and pick up a pack of blu carto's being as blu is 510 chances are good it will fit what you have.
Another option tho nic free would be go to wal mart get a bottle of vg sold in the first aid supplies as glycerin skin protectant and then over to the baking section and get a bottle of imitation extract, just read the labels as they are either pg or alcohol based.