Need 2 tickets to Alhambra for May 4 or May 5

You can still get in with an organized tour, although it will cost more. You can ask your hotel for assistance or you can try a tour consolidator like Viator. I was able to go during Semana Santa (extremely busy time) with a tour. It wasn't ideal, but it worked.

Be sure the tour includes entrance to the Nasrid Palaces. That's the difficult part. There's at least one company that has sold tickets without Nasrid-Palace access. You do not want that.

I visited just after the change in ticket sales in 2017, but I think that a 3 day Dobla D'oro ticket would be an option. It gives Alhambra and Nasrid Palace entries as well as access to the buildings associated with it in town. A little more expensive, but even if you only used it for Alhambra and Nasrid Palace, still a good price.
For what it is worth, I really enjoyed Nasrid Palace at night. I bought a general pass and a Dobla d'oro night visit, but was there for 5 nights.

Thanks for the advice. I'll be there in Granada for 2 days only, and am staying at Callejón del Gato, approx 1 km from Alhambra..
I've bought Dobla d'oro pass for night visit for May 4 at 10PM. The Gardens, Generalife and Alcazaba (7 EUR) is also available for May 4 and May 5. Would you recommend we do the general tour on May 4 or May 5. Also, what else would you recommend we do in Granada.

So, tickets weren't sold out? Your general ticket should include a timed entry to Nasrid palace. Even though I enjoyed doing the night visit before the day visit, I would book the day with a timeslot that works for you.

Sorry for the miscommunication. The (7 EUR) pass that allows entry into Gardens, Generalife and Alcazaba is available for May 4 and May 5.
I have updated my last comment as well.

So many choices, right? I was going to suggest doing it Saturday and just staying around for your evening hours, but looking at the schedule. Day time ends at 6pm and evening opens at 8pm, so 2 hours of lag time plus the 2 hours prior to your entry tickets. However, area entered from the Gate of Justice (not the main ticketing gate) leads to the areas open for free so you could stay on and have a leisurely (though a tad expensive) dinner at the Parador (hotel), there are a couple of places across the street from the Alhambra. There is also a museum that is open late and free, right by the entry line for the Nasrid Palace. Sunset is after 9pm, so you can watch it from the balastrades by the Nasrid palace with a glass of something bought at the little food kiosk.

Otherwise, either day could do....with only 2 days there, you may want to maximize your time. I went on the Saturday night, and then Sunday for the bulk of the property. I think that was because I wanted to see some of the other buildings on the Double d-Oro ticket that weren't open Sunday.
Check the date and times of the other tourist attractions you want to see and decide from there?
I was just a block or two from Callejon del Gato, but in an apartment, so didn't eat out much. You are near the top of the street (really a pedestrian alley) with a number of teterias, so if you like tea, try one of those. I found it a great area - not too hilly - and central for bus to airport or bus station, groceries, the Albicin, 'down town'. There are nice (but touristy) eateries along the Rio Darro which offer tourist menu del dias and a great place to enjoy the sun and people watch.
I think the bus numbers have changed, but I would suggest taking the bus up to the alhambra. It is a hefty walk uphill by road. There is a path down through the forest if you still have energy and want to walk back.

Thanks Maria,
I've booked the 10PM night visit for Saturday and Day visit on Sunday. I think both on the same day might be exhausting.

Glad you have tickets. Evening visit is late but won't be too onerous. However if jet lagged, then both would add up. Feel free to embrace la siesta. It makes Spanish meal time doable. Have a wonderful time.