Wow, you are really in a tight spot there. Literally no room to work with between the pump outlet and your filter. The elbow seems odd to me as well, but was short enough to work - for a while anyways. Well, I suspect the connection at the pump is cracked which explains the leak. Because of the outward pressure, that requires replacement. You may have to get creative and try to find some pool PVC connections that will fit. Perhaps turn-off the equipment for a while a take that piece with you either to the local hardware store, pool store, or just shop on-line as there are many vendors on-line that have supplies. If you do that and can't run the system for a couple days, consider increasing the FC level before shutting it down so that you have adequate chlorine in the water and don't end-up with algae trying to grow during the repair period. When you do shop, make sure to have all your pool info with you (pump & filter type, model, and fitting diameter). If you had a little more room, it might not be so tricky, but you're backed into a corner there.