Hi and welcome to the forum!
Sport-billy has already given you the diet links. Please be aware that guinea pigs need unlimited hay, which should make up to 80% of their daily food intake for healthy guts and for keeping the crucial back teeth ground down. Don't get any shop treats that contain seeds, sugar/honey and dairy products (including yoghurt); rather go for herbal forage treats. Make sure that you do not overfeed on veg, either!
Here is one about sow behaviour, which may help you when your girls come into a stronger season:
http://www.theguineapigforum.co.uk/forumdisplay.php?21-Behaviour
You can find lots of informative threads in our reference section or at the top of the other Care subsections. Please don't hesitate to ask any questions that you may have.
Wtih members from all over the world, we would be very grateful if added your country, state (US/OZ) or general area (UK) to your details, so we can give you appropriate advice, links and - if possible - local recommendations straight away. You can do so in forum/private messages (on top bar)/my settings/edit profile/location.
In my settings/edit avatar, you can create the picture that appears with your name.