Hi Shirl,
We have used a site just a few miles North of Poitiers a few times; this is the Parc de Loisir de St Cyr.
I would recommend this for a stopover or for longer stays. It is actually a little North of Poitiers - if you have a suitable map to check with, travelling South on the A10, take J27 just South of Chatellerault, then follow the N10 South; turn East (left) in Beaumont and I think it is signposted from there.
The site is situated beside a large lake and is part of a leisure park, with lake swimming and other water activities permitted, e.g. sailing tuition. There is also a gymnasium, shop and restaurant. The lakeside, which is fenced off from the caravan site (but accessible from it), is popular with the 'locals' for recreational use at weekends.
Prices are reasonable at (2006 prices) 11 or 22 Euros in low and high season respectively for pitch / two adults / electricity etc..
The site is part of the 'Flower' group of sites, and is listed in the Caravan Club Europe Sites Guide under Jaunay Clan.
I hope this may be useful to you.
Enjoy your holidays.
Trevor M