Mate, maybe give us a few more details. Your post is a bit vague. 😱
In the meantime, you can test whether it's the router or the internet connection dropping out by using the wireless network to transfer a large file between machines. If you get a constant stream, then you know something's up with the 'net. 🙂
If this isn't the case, then check for interference from devices such as microwaves, other routers, cordless phones and so on. 😎