Please take a deep breath! You can go back to the p@h you got your missexed couple from, preferably with a confirmation of the pregnancy by a vet. P@h have a policy of paying vet costs and should also provide you with a larger cage etc. to accommodate the unplanned youngsters.
How long have you had your guinea pigs and how long have they been together at your place? I guess they are your usual shop youngsters? Sadly, your problem is anything but rare. But it would be good to get an idea about how far along your girl is. We have a pregnancy section on here where experienced piggy people can advise you.
Here is a detailded guide for all aspects of pregnancy, including the different dietary needs that a pregnant sow has.
http://wheekers.proboards.com/index.cgi?board=library&action=display&thread=7303
http://www.guinealynx.info/reproduction.html
Like the others have said, please remove your boy asap - sows come into season within hours of giving birth and a rampant boar is the last thing you want around heavily pregnant sows and freshly born babies!
If there is a baby boar in the litter, he can be paired up with dad. Any girls can go and live with mum. Otherwise, you can have dad neutered. Neutering ops are often cheaper than all other operations - they tend to cost around £50, but you want to find a good vet.
We also have tips on cheap and affordable housing on this forum if you want to plump for more flexible housing.
If you really can't cope with more piggies, we can put to in contact with a reputable rescue that will only rehome piggies into home checked homes and never into single places. Please don't just dump any of your piggies - we see all too often the horrible results of what happens afterwards on here!
It would be good if your slept over it and considered your options with a calmer mind. Your boys can survive in a padded cardboard box for a day or two, provided you put some plastic under a towel so there are no leaks while you think things through and make your enquiries.