They have a fantastic zoo in Buda and we went to the most amazing restaurant which is well worth a visit...
http://www.sirlancelot.hu/
It's medieval style with live entertainment like sword fighting.
Budapest is pretty big but the metro (underground) system is great. One ticket per ride (so if you change lines it's another ticket) and you can buy tickets cheaper in books of 10. You have to stamp them in a little machine before you go through the gates where an inspector checks them.
We also did a day trip to Vienna which is three hours each way via train from Keleti Station (all three stations on the metro). Bratislava can be done this way as well. You can take the hydrafoil down the Danube but it's about 5 hours each way.
If you want to venture out there are caves you can get to by bus or Szezendre and Visegrad.
English is not hugely spoke, quite a few of the younger people do and staff in restaurants but not so likely in places like the metro stations.
German is quite widely spoken though.
If you need any more info, give me a shout (
[email protected]). Have piccies on FB if you want to see.