No probs both - Basically, wireless will do a job, end of! Just a bit of a compromise in quality and reliability, the offset being the installation challenges of a wired solution. Let me know if you want any other help or advice, I'm not an expert but have put quite a lot of time in to research...
Piece of string job, you can buy a package from Maplins for < £200 plus installation and cabling. Mine probably cost about £800 inclusive. You should be able to do something very effective within this range.
Pros and cons to whatever you do. Probably the biggest problem with IP cameras is that...
Did you upgrade the software yet? My mac mini is a 2006 version so won't support the version of OSX that is required for the upgrade, just wondered if it's worth while?
Give me a shout if you need mate, I've got a pretty complex setup after some burglary issues but it all depends on what you want to spend etc. My setup got 1 person 10 years and another 4 so maybe it was a good investment!
Edit - The simple view of mine is Hikvision Night vision CCTV dome...