I lived in Estoril for 30 years so I guess I can tell you a few things.
First of all you'll be staying at the best place possible, ESTORIL. Actually its not in Estoril, its in Monte Estoril, a quiet zone still. From there you can walk both to Estoril and visit the biggest casino in Europe ( gamble a little?) and Cascais. In Cascais you can find all the best restaurants possible. Fresh fish all over and tons of seafood. If you go a little further, to Guincho ( Ill leave you a link) you can eat at some of the best restaurants in Europe, like "Porto de Santa Maria" ( expensive...) and watch the numerous radical sea sports ( Guincho is known for a lot of Surf contests) among other sports. Also check Cabo da Roca ( the most occidental part of Europe).
I could go on forever but I'm sleepy and I really need to go, but regarding the Hotel.....hmmmmm... :| Nope, its not the best option. If you wanna pay a little more stay in one of these:
Luxury 5 stars:
http://www.cascaismirage.com/
http://www.palacioestorilhotel.com/
3 stars:
http://www.europehotelreservation.com/en…
Guincho:
http://www.strawberryworld-lisbon.com/li…
Any question you might have, email me. Ill be glad to help.