You need to add "tblQuickFixEngineering.InstalledOn >= GetDate() - 7" to the where statement of your query. 
I have altered the built-in report "Windows: installed Windows updates" to list only the assets on which a Windows update was installed during the last 7 days:
Select Top 1000000 tblAssets.AssetID,
  tblAssets.AssetName,
  tblAssets.Domain,
  tblAssets.Username,
  tblAssets.Userdomain,
  Coalesce(tsysOS.Image, tsysAssetTypes.AssetTypeIcon10) As icon,
  tblAssets.IPAddress,
  tsysIPLocations.IPLocation,
  tblAssetCustom.Manufacturer,
  tblAssetCustom.Model,
  tsysOS.OSname As OS,
  tblAssets.SP,
  tblAssets.Lastseen,
  tblAssets.Lasttried,
  tblQuickFixEngineeringUni.HotFixID,
  tblQuickFixEngineeringUni.Description,
  tblQuickFixEngineeringUni.FixComments,
  tblQuickFixEngineeringInstalledBy.InstalledBy,
  tblQuickFixEngineering.InstalledOn,
  tblQuickFixEngineering.Lastchanged As LastChanged
From tblAssets
  Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
  Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
  Inner Join tblState On tblState.State = tblAssetCustom.State
  Inner Join tsysIPLocations On tsysIPLocations.LocationID =
    tblAssets.LocationID
  Inner Join tblQuickFixEngineering On tblQuickFixEngineering.AssetID =
    tblAssets.AssetID
  Inner Join tblQuickFixEngineeringUni On tblQuickFixEngineeringUni.QFEID =
    tblQuickFixEngineering.QFEID
  Left Join tblQuickFixEngineeringInstalledBy
    On tblQuickFixEngineeringInstalledBy.InstalledByID =
    tblQuickFixEngineering.InstalledByID
  Left Join tsysOS On tsysOS.OScode = tblAssets.OScode
Where tblQuickFixEngineering.InstalledOn >= GetDate() - 7 And
  tblState.Statename = 'Active'
Order By tblAssets.Domain,
  tblAssets.AssetName,
  tblQuickFixEngineeringUni.HotFixID