You should be Ok to receive all the main 'high power' satellites. Hotbird is next to the old Astra
Sky analogue satellite and should work fine.
The new Astra
Sky satellite that you're getting freeview off is to the left of the other two (when looking from the back of the dish).
Part of the fun is finding the different satellite. If you have fixed your mount and find a satellite mark the dish position on the mount. Move to another and do the same. soon you will have a number of positions to view.
If you can get the freeview channels without satellite I would move to the old Astra/Hotbird positions, loads of FTA channels.
The LNB has two outputs but they both receive the same satellite (the one the dish is pointed at, at the time).
Don't think the receiver has two LNB inputs so a second LNB option may not be practical.
If you get hooked then you could add a motor to the dish and scan the skies. Then you would be better with a larger dish to get the best results. Just check that have no obstruction across the south horizon before you invest any more hard earned cash.