Extend an RT-3200 - best (wireless) way

Hi folks, after a search on extend 3200 didn't reveal any thing I thought I'd post a new thread. Apols in advance if covered already. I did find a great article/thread on the range of the 5300 so that prompts me to ask this here hoping someone can come up with best options

I went for an RT-3200 a year ago to plug into my Virgin SuperHub and create what I hoped would be a far "better" wifi signal throughout our house.
Result is far better indeed buuuut - The Issue - not quite good enough...

Extend an RT-3200 - best (wireless) way