there is a noticable different when using a more powerfull router, if your dad plans to use it aswell i'd suggest you guys bite the bullet and get something medium to high end, the reason is the percision with which the router will be made and operate, you can get a 3hp router for under 100$ here fine and dandy but it'll be all giggly, hard to fine tune and adjust, where as a 200$ router is just made better.
What you're looking for is an edge guide, a router that supports both 1/4" and 1/2" collets, and at least 1-3/4hp
I think the freud is the best deal on that site..
http://www.screwfix.com/app/sfd/cat/pro.js...=67333&id=17864
Also see if you can look into porter cable, if they're available in your country, i keep hearing great things about their routers.