I have the blonde equivalent of you. I get on really well with the new John Frieda 7 day volume stuff, it really works. I also love creating v loose waves and a bit of oompf with the diamond waves tong, and volume powder by Toni & Guy. Hope that helps a little ! PS dont chop it off, millions of people would love your hair.
If you want Jessica Alba, get a bit of ballayage and start practising beachy waves!
Yeah Label.M at Toni&Guy do something called Resurrection Style Dust. Its a volume powder but instead of wearing off, if you give your roots a bit of a massage it reactivates. Texturising Volume Spray by Label.M would also be amazing for you.