I'm glad you have come back and posted again, so you can perhaps get more help.
With the exercises, you have to do them every day- for life. The long holds are for up to 10 seconds each - and I'd also suggest looking at the website of Michelle Kenway a specialist physio who is the Oz equivalent of Gussie! There are some easy to watch videos on her website and she does a pelvic floor safe DVD for exercises, because she says some Pilates makes the pelvic floor worse.
see her video on how to do your PFE
www.pelvicexercises.com.au/pelvic-exercises-women-video/
If you can't wee properly sitting down it's possible you have a 'kink' in your urethra. This means it's sagging which makes the flow harder. This can be fixed with a TVT procedure- a small piece of tape through the vagina which lifts the urethra back into its proper position.
You would be advised to use Ovestin cream or Vagifem pessaries before any op- (it's a day case and done with local not GA) to tone up your tissues.
You might need to use this topical HRT for up to a year to get really good results.
Don't take notice of the 'not for over 60s' info- that's nonsense and I once saw a woman aged about 90 being given instructions by the nurse at my consultant's office!
My mum who is 87 uses it for dryness.
You may well need this to strengthen your tissues and help take away urgency and frequency.