Hi
I live in central reading - there are no cheap hotels with parking in the centre - either cheap with no parking, or expensive with parking. Holiday Inn Express has a car park - google for details - but its about half a mile from the TC.
Charvil is on the outskirts of Reading, on the A4 towards Maidenhead nr Twyford. If you actually need to be in Charvil, this is right there
http://www.weewaif.tablesir.com/accommodation. htm
my relatives have stayed there a few times when visiting and recommend it.
If you are staying in Reading and need to be travelling in rush hour allow plenty of time. In the morning, my car commute from town to just beyond Charvil can take up to an hour - and its always worse the week that schools go back. Traffic in Reading is generally a nightmare, but rush hour is really bad.
Cheers
RM