Oracle extents - How can I have so many with this small size?
The data you're getting from Toad appears to be incorrect or, at least, misleading.  If you are using a locally managed tablespace with automatic extent allocation, Oracle will determine your initial and next extent sizes automatically.  In 11.2, the first 16 extents are going to be 64k in size (for a total of 1 MB).  The next 63 extents are going to be 1 MB in size.  So if you have 26 extents, that implies that the table occupies 11 MB of space on disk.  An initial extent of 1.44 GB makes no sense and a size of 4.18 MB seems rather low if you're saying it hasn't shrunk.

What does

SELECT tablespace_name,
       extent_id, 
       bytes/1024 kb
  FROM user_extents
 WHERE segment_name = &lt;&lt;name of table&gt;&gt;


show you?  If you have 26 extents, you should see that extents 0-15 are 64 kb in size and extents 16-25 are 1 MB in size.  

SELECT SUM(bytes)/1024/1024 size_in_mb
  FROM user_extents
 WHERE segment_name = &lt;&lt;name of table&gt;&gt;


will show you the total size of the table's extents on disk.