5.6 does come with new presets – they are probably there. Look on the Support section of the Web Site for the Presets Manual for info.
It does sound as though you need to change the battery – I won't be able to look it up until the new Year, but do a search on these forums and you should find the type number. It's not hard to change – you need a cross-point screwdriver to remove the top of the unit.
It is important – they last about 5-10 years, but your unit may be older.