Suica and NEX retun card option

Hi all from Ireland ;-)

i am visiting for 15 days,

this card needs to be used in 14 days, is it possible to pay extra or will have to buy the one way combo yen 3500 then a single nex ticket on return yen 2940

thanks

No, you will not be able to use the roundtrip package. The oneway package plus a regular ticket would be one possibility. Or you could take the skyliner (or one of the other cheaper options) for the return journey. See this page for your options:

http://www.japan-guide.com/e/e2027.html

The one way N'Ex pass is good for only one direction: Narita Airport to Tokyo.....

will have to buy the one way combo yen 3500

In that case the cost for the way will be practically 1500 yen.
You will pay
2000 yen for a Suica Card (e-money of 1500 yen worth + 500 yen as a deposit) and
1500 yen for a special N'EX ticket.
This ticket can work both as a Ltd. Express ticket and as a base-fare ticket.
- http://www.jreast.co.jp/e/suica-nex/index.html

a single N'EX ticket on return yen 2940

The price is not always 2940 yen.
It's a total of the prices of a base fare and of a Ltd. Express charge; each of the prices depends on the distance.
You can pay a base fare and a Ltd. Express charge for different sections.
e.g.
2210 yen as a base fare for Kamakura -- Yokohama -- Narita Airport, and
2090 to 2490 yen as a Ltd. Express charge for Yokohama -- Narita Airport (on a N'EX).