NOTE : your hard disk has 61 reallocated sectors. Hard disks do have spare sectors (usually from 256 up to 1024) used to replace bad ones. This remapping operation is transparent to the end user. Anyway, this can lead to degradated performances (because remapped sectors are in different places of the disk than the original ones and the head needs additional moving). If reallocated sectors grow over time, you might encounter some serious troubles. A backup of the most important data is suggested anyway.  
 
NOTE : your hard disk has 20 pending sectors. Those are sectors that couldn't be properly read and that the hard disk logic is waiting for a write operation to try to remap to a spare sector (if available). According to the Reallocated Sector Count attribute, your hard disk seems to have available spare sectors. A simple disk surface scan won't be enough to force the remap operation. You need a read/write surface scan to remap the sector. The best option should be a tool that knows about what should be read from that sector so that it has some option to apply the best fix to the missing data.  
 
NOTE : your hard disk has 1379 offline uncorrectable sectors (this value is very large and your hard disk should be replaced). Those are sectors that an offline scanning found as unreadable. Offline scanning is a process that can be automatically started by the hard disk logic when a long enough idle period is detected or that can be forced by some tool. Those unreadable sectors are identified and the hard disk logic is waiting for a write command that will overwrite them to try to remap them to spare sectors (if available). According to the Reallocated Sector Count attribute, your hard disk seems to have available spare sectors. A simple disk surface scan won't be enough to force the remap operation. You need a read/write surface scan to remap the sector. The best option should be a tool that knows about what should be read from that sector so that it has some option to apply the best fix to the missing data.