unfortunately my wife doesn't work like that.
It's not that I don't have the money, I could spend $5k if I didn't have a marriage to worry about. My wife refuses to believe that spending more than $500 on a home theatre is 'worth it' (this despite her quite happily spending $1k on a pari of curtains for our bedroom, when we already had perfectly serviceable curtains in there in the 'wrong' colour)
although, maybe I could withdraw $50 a week in cash, save it up, then when I come to buy the HT I could put $500 on eftpos and the rest in cash. when she looks at the bank, it will look like $500. I would just have to hide the reciept...
If you are just getting the audio through the horrible TV speakers and want to improve the situation, then your options are;
1) do nothing
2) pay more than will be agreed by 'her indoors' and suffer
3) buy a basic HT in a box with at least 1 HDMI input and a 4 port HDMI switch
3 is probably at pretty good step forward and something you could live with.
That said http://www.jbhifi.co.nz/jb-hi-fi-home-audio/receiver/sony/7-2-channel-home-theatre-receiver-sku-237475/ at $396 - down from $677 would be worth a look wouldnt it?
They also have a 5.1 Wharfdale speaker pack for $277 - though the amp says its 7.2 I presume it can run in 5.1 mode....