Dia duit! It is always nice to see someone taking an interest in Irish history. I can recommend a text that I have read and that has been recommended to me. Thomas Bartlett's Ireland: A History is the book that has been recommended to me as a comprehensive, single-volume history of Ireland. R.F. Foster's textbook that you have mentioned above is considered a brilliant exemplar of revisionist history that still stands the test of time as an overview of Irish history. I would highly recommend both, but I found Bartlett a tad easier to read than Foster's volume.
The books regarding Irish (and British) history on this subreddit's booklist are rather good for introductory (and beyond!) reading. What you will find with regards to academic work is that it is very difficult to write a complete history of anything over an extended time-period, much less throughout time immemorial (to every first year undergrad student's dismay!).
I would also suggest you familiarize yourself with the facets of Irish historiography before you begin reading, as historiographic debates are particularly thorny and outspoken regarding Irish history. It is important to recognize the ideology of the book you are reading. Many volumes that you will find on the bookstore shelf, or even at your local library, are written by journalists or pop historians. These will most likely conform to a non-academically rigorous, nationalist retelling of historical events, which is a problem (in my eyes) when dealing with Irish history in particular.
Going back to your initial question, your best bet is to read Bartlett's book which I have mentioned, Foster's book (which you have already found), or pick something ad hoc on the booklist that interests you. Beyond that, the Cambridge History of Ireland is a four volume series which would (though it exceeds your parameters of a one-volume work) most likely satiate your intellectual thirst. If you have a particular interest in a time period in Irish history I would probably be able to point you in a more specific direction, as would the bibliographies of everything mentioned so far. I myself am an undergraduate student currently focusing on Early Modern Irish history, but with a broader interest in both the Modern and Early Modern periods, British colonialism, and the Irish diaspora in the Commonwealth during the 19th and 20th centuries. I hope this answers your question and aids you in your quest for knowledge. Slán!