None of the IHG properties are located near central Dublin, the closest being five or six miles out. There is no Hyatt property in Dublin. The Radisson Blu Royal is nice, but if you're staying for three nights and aren't a Club Carlson Visa holder so that you can't get your last night free, you won't have enough points. The one Marriott property is outside the city, and you don't have enough points. There are several Hilton properties, some of which are unavailable, some of which require more points than you have, and two, the Hilton Dublin and the Hilton Dublin Airport, where you could stay for one night with the points you have (you could actually do three nights at the airport hotel on a points and cash redemption but, again, you're away from central Dublin at that hotel).

The Westin is very nice and very well located. You may very well be able to stay there with the points you have, as it's a category 5 hotel, not requiring more than 48K points for a three-night redemption. But given that you're talking about a stay in less than eight weeks than encompasses St. Patrick's Day, there is no guarantee of availability. And if you have to pay cash, it's currently running at 505 euro at the lowest rate for 3/15-18.

In other words, you may need to line up your hotel in Dublin first as London has more options, especially with IHG and Club Carlson, and you should not delay long in making your reservations at the Westin because demand for a stay that includes St. Patrick's Day will be high.