You could buy a 2 day park hopper pass at the gates or from the
Disney store in Paris - on the Champs Elysee. Sorry Im not sure how much these cost but there is info in the FAQ sticky at the top of the page.
Your other option would be to buy a francilien annual pass which can sometimes work out cheaper however this cannot be used on the 2nd and 3rd day after purchase so would be ideal if you were doing 2 seperate days at DLP with Paris inbetween. The other thing to look out for is the blackout days for this pass - you would need to check that none fell on the days you were there - there is a list again in the FAQ sticky
As for dining - as you are off site you wont be able to get the half board vouchers.
There is a big range of restaurants both in the parks and in the village and hotels. Some are buffet meals, some are table service and there are also a lot of counter service in the parks.
The prices vary as well as the type of food they serve.
Have a look at some restaurant reviews - in the restaurant sticky at the top as there will be pictures, menu examples and ideas of prices. If you have any questions about specific places then ask
Happy Planning