Any reason you want to stick with Sony?
I think your best bet is the Sony Ericsson T715. It's around 9K. It's a great all round phone.
If you can stretch you budget a bit go for the Sony Ericsson YARI - Its got a decent camera at 5 MP, a little better than the T715's 3.2 MP. Might be a bit over your budget though at around 11.5k