VIENNA (Reuters) - A new poll by Austria s Social Democrats (SPO) suggests they may be poised for a boost at parliamentary elections on Sunday after having been relegated to third place behind the conservatives and the far right in opinion polls for months. An SPO source and a report by newspaper Kurier said on Friday the Social Democrats have come within less than a handful of percentage points of the conservatives, who have been leading polls for months at around a third of the vote. The SPO and the far-right Freedom Party (FPO) have both attracted approval ratings of around a quarter, with the FPO taking second place more often than not.  We will win this, you will see,  an ebullient Christian Kern, Social Democrat Chancellor and party leader, told supporters. Whichever party wins the most votes on Sunday is likely to miss the 50-percent mark, meaning it will have to enter coalition talks. 