16.62p for first 2kwh/day then 13.32p so in 24hours = 33.24(10hours at 16.62) + 37.296(14hours at 13.32) = 70.536p/day.
Most likely you already use 2 kwh/day before accounting for the rig so you should calculate at the 13.32p rate. That means it costs you 64p
Mining at 290Mhash/s so 0.14btc/day average. at £10/btc = £1.40. Or currently £6/btc so... 0.84p
Profit today = 13p...
290 actualy should generate 0.154 btc a day so thats 28.4p a day
In all honesty though you really need a rig that has 4+ cards in it. For example my best rig which is 5 5850's requires about 1000 watts and generates about 1.925 ghash. That's 1.025 btc a day. Using your rate for electricity it costs 3.20 pounds a day. Making 1.025 btc a day and subtracting the electricity would be 2.95 pounds per day.
Keep in mind though the price may go up in the future and any btc you don't sell now could be worth alot later on. Lets say you didnt spend any btc and just paid your bill for a 2 months and then it jumps to 18 pounds a btc. That means the 9.24 btc(I realize this isn't exactly accurate) you saved up is worth 166.32 pounds. The cost in electricity for the 2 months would be 17 pounds.
That means you made 149.32 pounds so its all about when your willing to sell your bitcoins.
18 pounds a BTC -- isn't that $30?
I think there are a lot of people (even among miners) who have accepted that $30 isn't coming around again any time soon -- if ever.
I personally would be ecstatic to see $15 again, nevermind $30.
After this long at $9.50, if we hit even a modest spike to $12 there would be a massive flood of selling. It's human/market psychology.