Ditto about getting plants from people here when you can. I've bought my plants almost exclusively from people on here, and I always get nice amounts for good prices.
Anyway, since you can't add more plants right now, I would suggest getting a nice piece of driftwood (something twisted and root-like would look amazing) to put slightly off-center towards the back. I'd also attach the anubias and the Java ferns to your driftwood. IMHO, they do the best and look the best attached to driftwood and are much easier to rearrange for fun or cleaning.
I agree that bunching the plants in a couple spots rather than spreading them would look more natural and have an effect of looking more full. For example, I would move the crypt a little more to the right. I would attach the javas, as mentioned, to the driftwood and put them sort of leaning across one corner of the tank or something like that. I would move the anubia more towards the back center so that it is more of a focal point. Then I'd tie the moss to either driftwood or rocks with thread and then put it more towards the front since it's the shortest thing you've got right now.