I am sure you meant to say Depth of Field, not bokeh.
Anyway, I do not know of any websites that will do this for you, I also highly doubt that there is one (unless somebody proves me wrong!). Effects like this can be recreated in Photoshop using Gaussian Blur for example, but this method is time consuming and the results are never as good as getting it right at the time of shooting.
Your best bet (if you want to do it for free) is to download GIMP and see if these is a tutorial online giving a method on how to do this using GIMP (it is fairly similar to Photoshop).
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