Advice on lighting Kit - budget of £4000

Hi everybody,

We are in the process of upgrading our lighting kit and have an allocated budget of around £4000 (around $6500). We do mainly corporate which includes interviews and greenscreen stuff. For the greenscreen we have a Reflecmedia Chromaflex Studio Bundle (http://www.reflecmedia.com/education/products/all-in-one-studio-bundles/index.htm) which includes 2 iztac lights (http://www.reflecmedia.com/education/products/iztac/index.htm). We also have 2 Photobeam 800, and that's about it.
We shoot on Sony Ex1 and are also getting a FS-700 with Ninja recorder to get a better picture for keying, but obviously lighting is the most important part of the equation.
Please take into account that we cannot go for ebay or DIY solutions as we need to make the purchases from reputed sellers (tender procedures).
Any help is really appreciated and I would like to thank you all in advance.

Alberto

Alberto Corredor Marina
Long Shot Media Ltd
London, UK