Ok so are you wanting to stay in Christchurch at all?
Id probably reccomend something like this:
Saturday 27th March - Christchurch
Stay at the Holiday Inn Central City (great location) and then just have a wonder around the shops and all that on the Saturday (was going to suggest the Gondola but I wouldnt bother Id do it in Queenstown instead WAY better there)
Saturday night, go out for tea (heaps of funky places to choose from) then go into SOL Square for a drink, maybe over to the Casino for a look have great bands etc playing
Sunday: Go to the Arts Centre in town for a look around and you HAVE to get a Costers Suvalarki from there - AMAZING. Lots to see and do in the City but really dont know on your budget.
Monday: Go to Akaroa (about an hour) - what an amazing beautiful place especially if your on your honeymoon. Id get a house from http://www.akaroarentalhomes.co.nz/fastpage/fpengine.php/templateid/1 seems to be cheaper than motels and a lot nicer etc because its bigger.
Id suggest 2 nights in Akaroa.
Totally have fish n chips one night for tea there - they are brillant there!
Wednesday: Drive back from Akaroa to Christchurch stay in Christchurch at Hotel So (just remembered that place its nice and CHEAP as)
Thursday: Drive to Hanmer Springs (about 1.5 hour) they have hot pools there which are awesome! You will love it! Really Alpiney there great for walks and stuff - its lovely. Again get a holiday house there (www.hanmerholidayhomes.co.nz) and that way you can save some money by getting food from the supermarket for lunches and teas etc. Stay there maybe 2 nights as well.
Saturday: Drive back from Hanmer, stay at Hotel So again in Christchurch
Sunday: I would try and get flights from Christchurch to Queenstown (you can get some really cheap ones for $29 each way at the moment) otherwise its like a 7 hour drive! And you wont really need a car in Queenstown at all so I would highly suggest doing that!
If not you would probably need the rest of the week just going to Queenstown because its a whole day driving there and then driving back, plus a couple of days to get over the driving if that makes sense.
So look into flying and if thats an option come back to me and I'll give you some options for the other days when you fly back here!
Exciting times!