Hello Kamran, there are many to choose from & I am sure others here will advise you differently & I say check out all reccommendations should any more follow.
But to try & stay in your budget of which you haven't suggested as it hasn't been asked, but let's stick with the £70 of the lens & a cheap flash I put forward & the same cost as Big Soft Moose did at £50 for the lens.
These flash units go for £250 when they first came out, they have been superseeded by a newer version but this one does have a service upgrade port,
http://www.nissindigital.com/Di622.html
However, the mkII is already firmware upgraded for your camera the 1100d,
http://www.nissindigital.com/compatibilitychart.html
As to price try here,
http://www.microglobe.co.uk/advance...igital+di622&gclid=CMvNiKO1oMMCFTHMtAod4zQA9w
http://www.ebay.co.uk/itm/NISSIN-Di...ories_CameraFlashUnits_JN&hash=item259e038463
http://www.ebay.co.uk/itm/Nissin-Di...ories_CameraFlashUnits_JN&hash=item2edc5b1583
The 3rd price option has only 1 day 5 hours left & at the moment is dirt cheap, don't bid until the last 20 seconds if you can & the price isn't to high.
I have seen some old new stock around for £120-50, remember this was £250 when it first came out.
Also there are better flashes but for the money you won't get much if any more features etc.
Find your own reviews of course but of those I have checked this unit seems very capable certainly for the price, especially if you can get it for that cheap (at the moment) 2nd eBay offer.
Also it has a slave function so can be used later when/if you upgrade the flash so don't throw it away if you buy one.
On another note, when money allows, buy the 50mm f/1.8 lens, you won't be disapointed. It may seem like a waste given you have the 18-55mm so the 50mm range is covered, but it's the f/1.8 you need to experience.
Having said that if when you come to think about one you may have funds enough for the 50mm f/1.4 or even the f/1.2 version, then again I saw the f/1.0 go for a tad over £2000 over this past weekend.
Happy hunting for the next purchase....